diff --git a/core/thread/thread_variable_get_spec.rb b/core/thread/thread_variable_get_spec.rb
index 2eff1686f..67017771f 100644
--- a/core/thread/thread_variable_get_spec.rb
+++ b/core/thread/thread_variable_get_spec.rb
@@ -23,9 +23,10 @@
     Thread.current.thread_variable_get(:thread_variable_get_spec).should be_nil
   end
 
-  it "converts a String key into a Symbol" do
-    @t.thread_variable_set(:a, 49)
-    @t.thread_variable_get('a').should == 49
+  it "accepts String and Symbol keys interchangeably" do
+    @t.thread_variable_set("a", 49)
+    @t.thread_variable_get("a").should == 49
+    @t.thread_variable_get(:a).should == 49
   end
 
   it "converts a key that is neither String nor Symbol with #to_str" do
diff --git a/core/thread/thread_variable_set_spec.rb b/core/thread/thread_variable_set_spec.rb
index f8f790dc0..c262a6614 100644
--- a/core/thread/thread_variable_set_spec.rb
+++ b/core/thread/thread_variable_set_spec.rb
@@ -24,9 +24,12 @@
     Thread.current.thread_variable_get(:thread_variable_get_spec).should be_nil
   end
 
-  it "converts a String key into a Symbol" do
+  it "accepts String and Symbol keys interchangeably" do
     @t.thread_variable_set('a', 49)
-    @t.thread_variable_get(:a).should == 49
+    @t.thread_variable_get('a').should == 49
+
+    @t.thread_variable_set(:a, 50)
+    @t.thread_variable_get('a').should == 50
   end
 
   it "converts a key that is neither String nor Symbol with #to_str" do
diff --git a/core/thread/thread_variable_spec.rb b/core/thread/thread_variable_spec.rb
index 041c9f438..d64e6ec63 100644
--- a/core/thread/thread_variable_spec.rb
+++ b/core/thread/thread_variable_spec.rb
@@ -19,9 +19,14 @@
     @t.thread_variable?(:a).should be_true
   end
 
-  it "converts a String key into a Symbol" do
+  it "accepts String and Symbol keys interchangeably" do
+    @t.thread_variable?('a').should be_false
+    @t.thread_variable?(:a).should be_false
+
     @t.thread_variable_set(:a, 49)
+
     @t.thread_variable?('a').should be_true
+    @t.thread_variable?(:a).should be_true
   end
 
   it "converts a key that is neither String nor Symbol with #to_str" do