diff --git a/base/strings/string.jl b/base/strings/string.jl
index e3a9cd56df201..c818e2e1844fb 100644
--- a/base/strings/string.jl
+++ b/base/strings/string.jl
@@ -252,7 +252,7 @@ function getindex_continued(s::String, i::Int, u::UInt32)
     return reinterpret(Char, u)
 end
 
-getindex(s::String, r::UnitRange{<:Integer}) = s[Int(first(r)):Int(last(r))]
+getindex(s::String, r::AbstractUnitRange{<:Integer}) = s[Int(first(r)):Int(last(r))]
 
 @inline function getindex(s::String, r::UnitRange{Int})
     isempty(r) && return ""
diff --git a/base/strings/substring.jl b/base/strings/substring.jl
index 3e99cc7477446..0da09f36be931 100644
--- a/base/strings/substring.jl
+++ b/base/strings/substring.jl
@@ -252,4 +252,4 @@ function filter(f, s::Union{String, SubString{String}})
     return String(out)
 end
 
-getindex(s::AbstractString, r::UnitRange{<:Integer}) = SubString(s, r)
+getindex(s::AbstractString, r::AbstractUnitRange{<:Integer}) = SubString(s, r)