diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3d6a15ac40..f53a8dea7c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Features
+
+- Add strict trace continuation support ([#4981](https://github.com/getsentry/sentry-dotnet/pull/4981))
+
 ### Fixes
 
 - The SDK now logs a `Warning` instead of an `Error` when being ratelimited ([#4927](https://github.com/getsentry/sentry-dotnet/pull/4927))
diff --git a/src/Sentry/Dsn.cs b/src/Sentry/Dsn.cs
index 011af39169..6a1d9934c1 100644
--- a/src/Sentry/Dsn.cs
+++ b/src/Sentry/Dsn.cs
@@ -38,13 +38,20 @@ internal sealed class Dsn
     /// </summary>
     private Uri ApiBaseUri { get; }
 
+    /// <summary>
+    /// The organization ID parsed from the DSN host (e.g., <c>o1</c> in <c>o1.ingest.us.sentry.io</c> yields <c>"1"</c>).
+    /// Returns <c>null</c> if no org ID is present in the DSN.
+    /// </summary>
+    public string? OrgId { get; internal set; }
+
     private Dsn(
         string source,
         string projectId,
         string? path,
         string? secretKey,
         string publicKey,
-        Uri apiBaseUri)
+        Uri apiBaseUri,
+        string? orgId = null)
     {
         Source = source;
         ProjectId = projectId;
@@ -52,6 +59,7 @@ private Dsn(
         SecretKey = secretKey;
         PublicKey = publicKey;
         ApiBaseUri = apiBaseUri;
+        OrgId = orgId;
     }
 
     public Uri GetStoreEndpointUri() => new(ApiBaseUri, "store/");
@@ -93,6 +101,19 @@ public static Dsn Parse(string dsn)
             throw new ArgumentException("Invalid DSN: A Project Id is required.");
         }
 
+        // Parse org ID from host (e.g., "o1.ingest.us.sentry.io" -> "1")
+        string? orgId = null;
+        var hostParts = uri.DnsSafeHost.Split('.');
+        if (hostParts.Length > 0)
+        {
+            var firstPart = hostParts[0];
+            if (firstPart.Length >= 2 && firstPart[0] == 'o' &&
+                ulong.TryParse(firstPart.Substring(1), out _))
+            {
+                orgId = firstPart.Substring(1);
+            }
+        }
+
         var apiBaseUri = new UriBuilder
         {
             Scheme = uri.Scheme,
@@ -107,7 +128,8 @@ public static Dsn Parse(string dsn)
             path,
             secretKey,
             publicKey,
-            apiBaseUri);
+            apiBaseUri,
+            orgId);
     }
 
     public static Dsn? TryParse(string? dsn)
diff --git a/src/Sentry/DynamicSamplingContext.cs b/src/Sentry/DynamicSamplingContext.cs
index f39d7fa5a7..61f0e6aa5e 100644
--- a/src/Sentry/DynamicSamplingContext.cs
+++ b/src/Sentry/DynamicSamplingContext.cs
@@ -30,7 +30,8 @@ private DynamicSamplingContext(SentryId traceId,
         string? release = null,
         string? environment = null,
         string? transactionName = null,
-        IReplaySession? replaySession = null)
+        IReplaySession? replaySession = null,
+        string? orgId = null)
     {
         // Validate and set required values
         if (traceId == SentryId.Empty)
@@ -95,6 +96,11 @@ private DynamicSamplingContext(SentryId traceId,
             items.Add("replay_id", replayId.ToString());
         }
 
+        if (!string.IsNullOrWhiteSpace(orgId))
+        {
+            items.Add("org_id", orgId);
+        }
+
         _items = items;
     }
 
@@ -200,7 +206,8 @@ public static DynamicSamplingContext CreateFromTransaction(TransactionTracer tra
             release,
             environment,
             transactionName,
-            replaySession);
+            replaySession,
+            orgId: options.GetEffectiveOrgId());
     }
 
     public static DynamicSamplingContext CreateFromUnsampledTransaction(UnsampledTransaction transaction, SentryOptions options, IReplaySession? replaySession)
@@ -225,7 +232,8 @@ public static DynamicSamplingContext CreateFromUnsampledTransaction(UnsampledTra
             release,
             environment,
             transactionName,
-            replaySession);
+            replaySession,
+            orgId: options.GetEffectiveOrgId());
     }
 
     public static DynamicSamplingContext CreateFromPropagationContext(SentryPropagationContext propagationContext, SentryOptions options, IReplaySession? replaySession)
@@ -241,7 +249,8 @@ public static DynamicSamplingContext CreateFromPropagationContext(SentryPropagat
             null,
             release: release,
             environment: environment,
-            replaySession: replaySession
+            replaySession: replaySession,
+            orgId: options.GetEffectiveOrgId()
             );
     }
 }
diff --git a/src/Sentry/Internal/Hub.cs b/src/Sentry/Internal/Hub.cs
index be71b2f1d3..9eb32facda 100644
--- a/src/Sentry/Internal/Hub.cs
+++ b/src/Sentry/Internal/Hub.cs
@@ -355,7 +355,14 @@ public TransactionContext ContinueTrace(
         string? name = null,
         string? operation = null)
     {
-        var propagationContext = SentryPropagationContext.CreateFromHeaders(_options.DiagnosticLogger, traceHeader, baggageHeader, _replaySession);
+        if (!ShouldContinueTrace(baggageHeader))
+        {
+            _options.LogDebug("Not continuing trace due to org ID validation. Starting new trace.");
+            traceHeader = null;
+            baggageHeader = null;
+        }
+
+        var propagationContext = SentryPropagationContext.CreateFromHeaders(_options.DiagnosticLogger, traceHeader, baggageHeader, _replaySession, _options.GetEffectiveOrgId());
         ConfigureScope(static (scope, propagationContext) => scope.SetPropagationContext(propagationContext), propagationContext);
 
         return new TransactionContext(
@@ -368,6 +375,39 @@ public TransactionContext ContinueTrace(
             isParentSampled: traceHeader?.IsSampled);
     }
 
+    internal bool ShouldContinueTrace(BaggageHeader? baggageHeader)
+    {
+        var sdkOrgId = _options.GetEffectiveOrgId();
+
+        string? baggageOrgId = null;
+        if (baggageHeader is not null)
+        {
+            var sentryMembers = baggageHeader.GetSentryMembers();
+            sentryMembers.TryGetValue("org_id", out baggageOrgId);
+        }
+
+        // Mismatched org IDs always cause a new trace, regardless of strict mode
+        if (!string.IsNullOrEmpty(sdkOrgId) && !string.IsNullOrEmpty(baggageOrgId) && sdkOrgId != baggageOrgId)
+        {
+            return false;
+        }
+
+        // In strict mode, both must be present and match
+        if (_options.StrictTraceContinuation)
+        {
+            // If both are missing, continue (nothing to compare)
+            if (string.IsNullOrEmpty(sdkOrgId) && string.IsNullOrEmpty(baggageOrgId))
+            {
+                return true;
+            }
+
+            // Both must be present and equal
+            return sdkOrgId == baggageOrgId;
+        }
+
+        return true;
+    }
+
     public void StartSession()
     {
         // Attempt to recover persisted session left over from previous run
diff --git a/src/Sentry/SentryOptions.cs b/src/Sentry/SentryOptions.cs
index 7fc69a600f..7e4f8bdc29 100644
--- a/src/Sentry/SentryOptions.cs
+++ b/src/Sentry/SentryOptions.cs
@@ -448,6 +448,24 @@ public string? Dsn
     internal Dsn? _parsedDsn;
     internal Dsn ParsedDsn => _parsedDsn ??= Sentry.Dsn.Parse(Dsn!);
 
+    /// <summary>
+    /// Returns the effective org ID, preferring <see cref="OrgId"/> if set, otherwise falling back to the DSN-parsed value.
+    /// </summary>
+    internal string? GetEffectiveOrgId()
+    {
+        if (!string.IsNullOrWhiteSpace(OrgId))
+        {
+            return OrgId;
+        }
+
+        if (!string.IsNullOrWhiteSpace(Dsn))
+        {
+            return ParsedDsn.OrgId;
+        }
+
+        return null;
+    }
+
     private readonly Lazy<string> _sentryBaseUrl;
 
     internal bool IsSentryRequest(string? requestUri) =>
@@ -1032,6 +1050,28 @@ public IList<StringOrRegex> TracePropagationTargets
     /// <seealso href="https://develop.sentry.dev/sdk/telemetry/traces/#propagatetraceparent"/>
     public bool PropagateTraceparent { get; set; }
 
+    /// <summary>
+    /// Controls trace continuation from third-party services that happen to be instrumented by Sentry.
+    /// </summary>
+    /// <remarks>
+    /// When enabled, the SDK will require org IDs from baggage to match for continuing the trace.
+    /// If the incoming trace does not contain an org ID and this option is <c>true</c>, a new trace will be started.
+    /// When disabled (default), incoming traces without org IDs will be continued as normal,
+    /// but mismatched org IDs will always cause a new trace to be started regardless of this setting.
+    /// </remarks>
+    public bool StrictTraceContinuation { get; set; }
+
+    /// <summary>
+    /// Configures the org ID used for trace propagation and features like <see cref="StrictTraceContinuation"/>.
+    /// </summary>
+    /// <remarks>
+    /// In most cases the org ID is already parsed from the DSN (e.g., <c>o1</c> in
+    /// <c>https://key@o1.ingest.us.sentry.io/123</c> yields org ID <c>"1"</c>).
+    /// Use this option when non-standard Sentry DSNs are used, such as self-hosted or when using a local Relay.
+    /// When set, this value overrides the org ID parsed from the DSN.
+    /// </remarks>
+    public string? OrgId { get; set; }
+
     internal ITransactionProfilerFactory? TransactionProfilerFactory { get; set; }
 
     private StackTraceMode? _stackTraceMode;
diff --git a/src/Sentry/SentryPropagationContext.cs b/src/Sentry/SentryPropagationContext.cs
index 6183262241..a19d8f7b39 100644
--- a/src/Sentry/SentryPropagationContext.cs
+++ b/src/Sentry/SentryPropagationContext.cs
@@ -48,7 +48,7 @@ public SentryPropagationContext(SentryPropagationContext? other)
         _dynamicSamplingContext = other?._dynamicSamplingContext;
     }
 
-    public static SentryPropagationContext CreateFromHeaders(IDiagnosticLogger? logger, SentryTraceHeader? traceHeader, BaggageHeader? baggageHeader, IReplaySession replaySession)
+    public static SentryPropagationContext CreateFromHeaders(IDiagnosticLogger? logger, SentryTraceHeader? traceHeader, BaggageHeader? baggageHeader, IReplaySession replaySession, string? sdkOrgId = null)
     {
         logger?.LogDebug("Creating a propagation context from headers.");
 
@@ -58,6 +58,19 @@ public static SentryPropagationContext CreateFromHeaders(IDiagnosticLogger? logg
             return new SentryPropagationContext();
         }
 
+        // Check for org ID mismatch between SDK configuration and incoming baggage
+        if (!string.IsNullOrEmpty(sdkOrgId) && baggageHeader is not null)
+        {
+            var sentryMembers = baggageHeader.GetSentryMembers();
+            if (sentryMembers.TryGetValue("org_id", out var baggageOrgId)
+                && !string.IsNullOrEmpty(baggageOrgId)
+                && sdkOrgId != baggageOrgId)
+            {
+                logger?.LogInfo("Org ID mismatch (SDK: {0}, baggage: {1}). Starting new trace.", sdkOrgId, baggageOrgId);
+                return new SentryPropagationContext();
+            }
+        }
+
         var dynamicSamplingContext = baggageHeader?.CreateDynamicSamplingContext(replaySession);
         return new SentryPropagationContext(traceHeader.TraceId, traceHeader.SpanId, dynamicSamplingContext);
     }
diff --git a/test/Sentry.Tests/ApiApprovalTests.Run.DotNet10_0.verified.txt b/test/Sentry.Tests/ApiApprovalTests.Run.DotNet10_0.verified.txt
index 64869d4587..0c8b3542b7 100644
--- a/test/Sentry.Tests/ApiApprovalTests.Run.DotNet10_0.verified.txt
+++ b/test/Sentry.Tests/ApiApprovalTests.Run.DotNet10_0.verified.txt
@@ -823,6 +823,7 @@ namespace Sentry
         public int MaxCacheItems { get; set; }
         public int MaxQueueItems { get; set; }
         public Sentry.Extensibility.INetworkStatusListener? NetworkStatusListener { get; set; }
+        public string? OrgId { get; set; }
         public double? ProfilesSampleRate { get; set; }
         public bool PropagateTraceparent { get; set; }
         public string? Release { get; set; }
@@ -838,6 +839,7 @@ namespace Sentry
         public System.TimeSpan ShutdownTimeout { get; set; }
         public string SpotlightUrl { get; set; }
         public Sentry.StackTraceMode StackTraceMode { get; set; }
+        public bool StrictTraceContinuation { get; set; }
         public System.Collections.Generic.IList<Sentry.StringOrRegex> TagFilters { get; set; }
         public System.Collections.Generic.IList<Sentry.StringOrRegex> TracePropagationTargets { get; set; }
         public double? TracesSampleRate { get; set; }
diff --git a/test/Sentry.Tests/ApiApprovalTests.Run.DotNet8_0.verified.txt b/test/Sentry.Tests/ApiApprovalTests.Run.DotNet8_0.verified.txt
index 64869d4587..0c8b3542b7 100644
--- a/test/Sentry.Tests/ApiApprovalTests.Run.DotNet8_0.verified.txt
+++ b/test/Sentry.Tests/ApiApprovalTests.Run.DotNet8_0.verified.txt
@@ -823,6 +823,7 @@ namespace Sentry
         public int MaxCacheItems { get; set; }
         public int MaxQueueItems { get; set; }
         public Sentry.Extensibility.INetworkStatusListener? NetworkStatusListener { get; set; }
+        public string? OrgId { get; set; }
         public double? ProfilesSampleRate { get; set; }
         public bool PropagateTraceparent { get; set; }
         public string? Release { get; set; }
@@ -838,6 +839,7 @@ namespace Sentry
         public System.TimeSpan ShutdownTimeout { get; set; }
         public string SpotlightUrl { get; set; }
         public Sentry.StackTraceMode StackTraceMode { get; set; }
+        public bool StrictTraceContinuation { get; set; }
         public System.Collections.Generic.IList<Sentry.StringOrRegex> TagFilters { get; set; }
         public System.Collections.Generic.IList<Sentry.StringOrRegex> TracePropagationTargets { get; set; }
         public double? TracesSampleRate { get; set; }
diff --git a/test/Sentry.Tests/ApiApprovalTests.Run.DotNet9_0.verified.txt b/test/Sentry.Tests/ApiApprovalTests.Run.DotNet9_0.verified.txt
index 64869d4587..0c8b3542b7 100644
--- a/test/Sentry.Tests/ApiApprovalTests.Run.DotNet9_0.verified.txt
+++ b/test/Sentry.Tests/ApiApprovalTests.Run.DotNet9_0.verified.txt
@@ -823,6 +823,7 @@ namespace Sentry
         public int MaxCacheItems { get; set; }
         public int MaxQueueItems { get; set; }
         public Sentry.Extensibility.INetworkStatusListener? NetworkStatusListener { get; set; }
+        public string? OrgId { get; set; }
         public double? ProfilesSampleRate { get; set; }
         public bool PropagateTraceparent { get; set; }
         public string? Release { get; set; }
@@ -838,6 +839,7 @@ namespace Sentry
         public System.TimeSpan ShutdownTimeout { get; set; }
         public string SpotlightUrl { get; set; }
         public Sentry.StackTraceMode StackTraceMode { get; set; }
+        public bool StrictTraceContinuation { get; set; }
         public System.Collections.Generic.IList<Sentry.StringOrRegex> TagFilters { get; set; }
         public System.Collections.Generic.IList<Sentry.StringOrRegex> TracePropagationTargets { get; set; }
         public double? TracesSampleRate { get; set; }
diff --git a/test/Sentry.Tests/ApiApprovalTests.Run.Net4_8.verified.txt b/test/Sentry.Tests/ApiApprovalTests.Run.Net4_8.verified.txt
index fbf517dd1e..7bfe25a6a4 100644
--- a/test/Sentry.Tests/ApiApprovalTests.Run.Net4_8.verified.txt
+++ b/test/Sentry.Tests/ApiApprovalTests.Run.Net4_8.verified.txt
@@ -809,6 +809,7 @@ namespace Sentry
         public int MaxCacheItems { get; set; }
         public int MaxQueueItems { get; set; }
         public Sentry.Extensibility.INetworkStatusListener? NetworkStatusListener { get; set; }
+        public string? OrgId { get; set; }
         public double? ProfilesSampleRate { get; set; }
         public bool PropagateTraceparent { get; set; }
         public string? Release { get; set; }
@@ -824,6 +825,7 @@ namespace Sentry
         public System.TimeSpan ShutdownTimeout { get; set; }
         public string SpotlightUrl { get; set; }
         public Sentry.StackTraceMode StackTraceMode { get; set; }
+        public bool StrictTraceContinuation { get; set; }
         public System.Collections.Generic.IList<Sentry.StringOrRegex> TagFilters { get; set; }
         public System.Collections.Generic.IList<Sentry.StringOrRegex> TracePropagationTargets { get; set; }
         public double? TracesSampleRate { get; set; }
diff --git a/test/Sentry.Tests/HubTests.cs b/test/Sentry.Tests/HubTests.cs
index c8bb6ea702..a61632ac38 100644
--- a/test/Sentry.Tests/HubTests.cs
+++ b/test/Sentry.Tests/HubTests.cs
@@ -2662,6 +2662,126 @@ public void Dispose_CalledMultipleTimes_CleanupCalledOnlyOnce()
         // Assert
         integration.Disposed.Should().Be(1);
     }
+
+#nullable enable
+    [Theory]
+    // strict=false: matching org IDs -> continue
+    [InlineData(false, "1", "1", true)]
+    // strict=false: no incoming org ID -> continue (permissive)
+    [InlineData(false, "1", null, true)]
+    // strict=false: incoming org ID but no SDK org ID -> continue (permissive)
+    [InlineData(false, null, "1", true)]
+    // strict=false: both missing -> continue
+    [InlineData(false, null, null, true)]
+    // strict=false: mismatched org IDs -> new trace (always)
+    [InlineData(false, "1", "2", false)]
+    // strict=true: matching org IDs -> continue
+    [InlineData(true, "1", "1", true)]
+    // strict=true: no incoming org ID -> new trace (strict requires match)
+    [InlineData(true, "1", null, false)]
+    // strict=true: incoming org ID but no SDK org ID -> new trace (strict requires match)
+    [InlineData(true, null, "1", false)]
+    // strict=true: both missing -> continue (nothing to compare)
+    [InlineData(true, null, null, true)]
+    // strict=true: mismatched org IDs -> new trace
+    [InlineData(true, "1", "2", false)]
+    public void ContinueTrace_StrictTraceContinuation_ValidatesOrgId(
+        bool strict, string? sdkOrgId, string? baggageOrgId, bool expectContinued)
+    {
+        // Arrange
+        var incomingTraceId = SentryId.Parse("bc6d53f15eb88f4320054569b8c553d4");
+
+        _fixture.Options.StrictTraceContinuation = strict;
+        _fixture.Options.OrgId = sdkOrgId;
+
+        var hub = _fixture.GetSut();
+
+        var traceHeader = new SentryTraceHeader(incomingTraceId, SpanId.Parse("b72fa28504b07285"), true);
+
+        var baggageMembers = new List<KeyValuePair<string, string>>
+        {
+            { "sentry-trace_id", "bc6d53f15eb88f4320054569b8c553d4" },
+            { "sentry-public_key", "49d0f7386ad645858ae85020e393bef3" },
+            { "sentry-sample_rate", "1.0" }
+        };
+        if (baggageOrgId is not null)
+        {
+            baggageMembers.Add(new KeyValuePair<string, string>("sentry-org_id", baggageOrgId));
+        }
+        var baggageHeader = BaggageHeader.Create(baggageMembers);
+
+        // Act
+        var transactionContext = hub.ContinueTrace(traceHeader, baggageHeader, "test-name");
+
+        // Assert
+        if (expectContinued)
+        {
+            transactionContext.TraceId.Should().Be(incomingTraceId,
+                "trace should be continued when org IDs match or validation passes");
+        }
+        else
+        {
+            transactionContext.TraceId.Should().NotBe(incomingTraceId,
+                "a new trace should be started when org ID validation fails");
+        }
+    }
+
+    [Fact]
+    public void ContinueTrace_OrgIdFromDsn_IsUsedForValidation()
+    {
+        // Arrange - DSN with org ID "1" in the subdomain
+        _fixture.Options.Dsn = "https://key@o1.ingest.us.sentry.io/123";
+        _fixture.Options.StrictTraceContinuation = true;
+
+        var hub = _fixture.GetSut();
+
+        var incomingTraceId = SentryId.Parse("bc6d53f15eb88f4320054569b8c553d4");
+        var traceHeader = new SentryTraceHeader(incomingTraceId, SpanId.Parse("b72fa28504b07285"), true);
+
+        // Baggage with matching org_id=1
+        var baggageHeader = BaggageHeader.Create(new List<KeyValuePair<string, string>>
+        {
+            { "sentry-trace_id", "bc6d53f15eb88f4320054569b8c553d4" },
+            { "sentry-public_key", "49d0f7386ad645858ae85020e393bef3" },
+            { "sentry-sample_rate", "1.0" },
+            { "sentry-org_id", "1" }
+        });
+
+        // Act
+        var transactionContext = hub.ContinueTrace(traceHeader, baggageHeader, "test-name");
+
+        // Assert - should continue because org IDs match
+        transactionContext.TraceId.Should().Be(incomingTraceId);
+    }
+
+    [Fact]
+    public void ContinueTrace_OrgIdOptionOverridesDsn()
+    {
+        // Arrange - DSN has org ID "1", but OrgId option overrides to "2"
+        _fixture.Options.Dsn = "https://key@o1.ingest.us.sentry.io/123";
+        _fixture.Options.OrgId = "2";
+        _fixture.Options.StrictTraceContinuation = false;
+
+        var hub = _fixture.GetSut();
+
+        var incomingTraceId = SentryId.Parse("bc6d53f15eb88f4320054569b8c553d4");
+        var traceHeader = new SentryTraceHeader(incomingTraceId, SpanId.Parse("b72fa28504b07285"), true);
+
+        // Baggage with org_id=1 (matches DSN but not the override)
+        var baggageHeader = BaggageHeader.Create(new List<KeyValuePair<string, string>>
+        {
+            { "sentry-trace_id", "bc6d53f15eb88f4320054569b8c553d4" },
+            { "sentry-public_key", "49d0f7386ad645858ae85020e393bef3" },
+            { "sentry-sample_rate", "1.0" },
+            { "sentry-org_id", "1" }
+        });
+
+        // Act
+        var transactionContext = hub.ContinueTrace(traceHeader, baggageHeader, "test-name");
+
+        // Assert - should NOT continue because OrgId override (2) != baggage org_id (1)
+        transactionContext.TraceId.Should().NotBe(incomingTraceId);
+    }
 }
 
 #if NET6_0_OR_GREATER
diff --git a/test/Sentry.Tests/Protocol/DsnTests.cs b/test/Sentry.Tests/Protocol/DsnTests.cs
index 41e91b702e..b95b2171ec 100644
--- a/test/Sentry.Tests/Protocol/DsnTests.cs
+++ b/test/Sentry.Tests/Protocol/DsnTests.cs
@@ -277,6 +277,41 @@ public override string ToString()
         public static implicit operator Uri(DsnTestCase @case) => new($"{@case.Scheme}://{@case.Host}:{@case.Port}{@case.Path}/api/{@case.ProjectId}/store/");
     }
 
+    [Fact]
+    public void Parse_DsnWithOrgId_ParsesOrgId()
+    {
+        var dsn = Dsn.Parse("https://key@o1.ingest.us.sentry.io/123");
+        Assert.Equal("1", dsn.OrgId);
+    }
+
+    [Fact]
+    public void Parse_DsnWithLargeOrgId_ParsesOrgId()
+    {
+        var dsn = Dsn.Parse("https://key@o123456.ingest.us.sentry.io/123");
+        Assert.Equal("123456", dsn.OrgId);
+    }
+
+    [Fact]
+    public void Parse_DsnWithoutOrgId_OrgIdIsNull()
+    {
+        var dsn = Dsn.Parse("https://key@sentry.io/123");
+        Assert.Null(dsn.OrgId);
+    }
+
+    [Fact]
+    public void Parse_DsnWithNonNumericOrgId_OrgIdIsNull()
+    {
+        var dsn = Dsn.Parse("https://key@oabc.ingest.us.sentry.io/123");
+        Assert.Null(dsn.OrgId);
+    }
+
+    [Fact]
+    public void Parse_StandardValidDsn_NoOrgId()
+    {
+        var dsn = Dsn.Parse(ValidDsn);
+        Assert.Null(dsn.OrgId);
+    }
+
     private static void AssertEqual(DsnTestCase @case, Dsn dsn)
     {
         if (@case == null)
diff --git a/test/Sentry.Tests/SentryPropagationContextTests.cs b/test/Sentry.Tests/SentryPropagationContextTests.cs
index bb90359d0a..6c90e20a48 100644
--- a/test/Sentry.Tests/SentryPropagationContextTests.cs
+++ b/test/Sentry.Tests/SentryPropagationContextTests.cs
@@ -161,4 +161,48 @@ public void CreateFromHeaders_BaggageHeaderNotNull_CreatesPropagationContextWith
             Assert.Equal("bfd31b89a59d41c99d96dc2baf840ecd", Assert.Contains("replay_id", dsc.Items));
         }
     }
+
+    [Fact]
+    public void CreateFromHeaders_WithOrgMismatch_StartsNewTrace()
+    {
+        // Arrange
+        var incomingTraceId = SentryId.Create();
+        var traceHeader = new SentryTraceHeader(incomingTraceId, SpanId.Create(), null);
+        var baggageHeader = BaggageHeader.Create(new List<KeyValuePair<string, string>>
+        {
+            { "sentry-trace_id", incomingTraceId.ToString() },
+            { "sentry-public_key", "d4d82fc1c2c4032a83f3a29aa3a3aff" },
+            { "sentry-org_id", "2" }
+        });
+
+        // Act - SDK org ID is "1", but baggage has org_id "2"
+        var propagationContext = SentryPropagationContext.CreateFromHeaders(
+            null, traceHeader, baggageHeader, _fixture.InactiveReplaySession, sdkOrgId: "1");
+
+        // Assert - should start a new trace because org IDs don't match
+        Assert.NotEqual(incomingTraceId, propagationContext.TraceId);
+        Assert.Null(propagationContext.ParentSpanId);
+        Assert.Null(propagationContext._dynamicSamplingContext);
+    }
+
+    [Fact]
+    public void CreateFromHeaders_WithOrgMatch_ContinuesTrace()
+    {
+        // Arrange
+        var incomingTraceId = SentryId.Create();
+        var traceHeader = new SentryTraceHeader(incomingTraceId, SpanId.Create(), null);
+        var baggageHeader = BaggageHeader.Create(new List<KeyValuePair<string, string>>
+        {
+            { "sentry-trace_id", incomingTraceId.ToString() },
+            { "sentry-public_key", "d4d82fc1c2c4032a83f3a29aa3a3aff" },
+            { "sentry-org_id", "1" }
+        });
+
+        // Act - SDK org ID matches baggage org_id
+        var propagationContext = SentryPropagationContext.CreateFromHeaders(
+            null, traceHeader, baggageHeader, _fixture.InactiveReplaySession, sdkOrgId: "1");
+
+        // Assert - should continue the trace
+        Assert.Equal(incomingTraceId, propagationContext.TraceId);
+    }
 }