diff --git a/spec/std/string_spec.cr b/spec/std/string_spec.cr
index 6fbdebc7d0ce..13a07e03148f 100644
--- a/spec/std/string_spec.cr
+++ b/spec/std/string_spec.cr
@@ -1718,6 +1718,8 @@ describe "String" do
       "hello".tr("helo", "1212").should eq("12112")
       "this".tr("this", "ⓧ").should eq("ⓧⓧⓧⓧ")
       "über".tr("ü", "u").should eq("uber")
+      "aabbcc".tr("a", "xyz").should eq("xxbbcc")
+      "aabbcc".tr("a", "いろは").should eq("いいbbcc")
     end
 
     context "given no replacement characters" do
diff --git a/src/string.cr b/src/string.cr
index cc84d26345f9..fffebaad4095 100644
--- a/src/string.cr
+++ b/src/string.cr
@@ -1591,7 +1591,7 @@ class String
     return delete(from) if to.empty?
 
     if from.bytesize == 1
-      return gsub(from.unsafe_byte_at(0).unsafe_chr, to)
+      return gsub(from.unsafe_byte_at(0).unsafe_chr, to[0])
     end
 
     multi = nil