diff --git a/packages/plugin-legacy/README.md b/packages/plugin-legacy/README.md
index b5c3631ab2ac60..d5e55aa9c663d2 100644
--- a/packages/plugin-legacy/README.md
+++ b/packages/plugin-legacy/README.md
@@ -27,7 +27,7 @@ export default {
 }
 ```
 
-Terser must be installed because plugin-legacy uses Terser for minification.
+If [renderLegacyChunks](#renderlegacychunks) is `true` (default), Terser must be installed because plugin-legacy uses Terser to minify legacy chunks.
 
 ```sh
 npm add -D terser
diff --git a/packages/plugin-legacy/package.json b/packages/plugin-legacy/package.json
index 6d416fe5e96474..daeb28cb34e8e1 100644
--- a/packages/plugin-legacy/package.json
+++ b/packages/plugin-legacy/package.json
@@ -45,6 +45,11 @@
     "terser": "^5.4.0",
     "vite": "^3.0.0"
   },
+  "peerDependenciesMeta": {
+    "terser": {
+      "optional": true
+    }
+  },
   "devDependencies": {
     "@babel/core": "^7.18.9",
     "vite": "workspace:*"
diff --git a/packages/plugin-legacy/src/index.ts b/packages/plugin-legacy/src/index.ts
index ca79a56f160146..dc2d3a64f7bea7 100644
--- a/packages/plugin-legacy/src/index.ts
+++ b/packages/plugin-legacy/src/index.ts
@@ -648,7 +648,9 @@ async function buildPolyfillChunk(
   excludeSystemJS?: boolean
 ) {
   let { minify, assetsDir } = buildOptions
-  minify = minify ? 'terser' : false
+  if (format === 'iife') {
+    minify = minify ? 'terser' : false
+  }
   const res = await build({
     // so that everything is resolved from here
     root: path.dirname(fileURLToPath(import.meta.url)),