diff --git a/lib/execjs/external_runtime.rb b/lib/execjs/external_runtime.rb
index 258bd34..850fa4f 100644
--- a/lib/execjs/external_runtime.rb
+++ b/lib/execjs/external_runtime.rb
@@ -9,7 +9,7 @@ module ExecJS
       end
 
       def eval(source, options = {})
-        souce = source.encode('UTF-8') if source.respond_to?(:encode)
+        source = source.encode('UTF-8') if source.respond_to?(:encode)
 
         if /\S/ =~ source
           exec("return eval(#{MultiJson.encode("(#{source})")})")
@@ -17,7 +17,7 @@ module ExecJS
       end
 
       def exec(source, options = {})
-        souce = source.encode('UTF-8') if source.respond_to?(:encode)
+        source = source.encode('UTF-8') if source.respond_to?(:encode)
 
         compile_to_tempfile([@source, source].join("\n")) do |file|
           extract_result(@runtime.send(:exec_runtime, file.path))
diff --git a/lib/execjs/mustang_runtime.rb b/lib/execjs/mustang_runtime.rb
index f02a244..f6b8f86 100644
--- a/lib/execjs/mustang_runtime.rb
+++ b/lib/execjs/mustang_runtime.rb
@@ -7,7 +7,7 @@ module ExecJS
       end
 
       def exec(source, options = {})
-        souce = source.encode('UTF-8') if source.respond_to?(:encode)
+        source = source.encode('UTF-8') if source.respond_to?(:encode)
 
         if /\S/ =~ source
           eval "(function(){#{source}})()", options
@@ -15,7 +15,7 @@ module ExecJS
       end
 
       def eval(source, options = {})
-        souce = source.encode('UTF-8') if source.respond_to?(:encode)
+        source = source.encode('UTF-8') if source.respond_to?(:encode)
 
         if /\S/ =~ source
           unbox @v8_context.eval("(#{source})")
diff --git a/lib/execjs/ruby_racer_runtime.rb b/lib/execjs/ruby_racer_runtime.rb
index d026db7..db5582e 100644
--- a/lib/execjs/ruby_racer_runtime.rb
+++ b/lib/execjs/ruby_racer_runtime.rb
@@ -7,7 +7,7 @@ module ExecJS
       end
 
       def exec(source, options = {})
-        souce = source.encode('UTF-8') if source.respond_to?(:encode)
+        source = source.encode('UTF-8') if source.respond_to?(:encode)
 
         if /\S/ =~ source
           eval "(function(){#{source}})()", options
@@ -15,7 +15,7 @@ module ExecJS
       end
 
       def eval(source, options = {})
-        souce = source.encode('UTF-8') if source.respond_to?(:encode)
+        source = source.encode('UTF-8') if source.respond_to?(:encode)
 
         if /\S/ =~ source
           unbox @v8_context.eval("(#{source})")
diff --git a/lib/execjs/ruby_rhino_runtime.rb b/lib/execjs/ruby_rhino_runtime.rb
index 2b90998..0c5aa24 100644
--- a/lib/execjs/ruby_rhino_runtime.rb
+++ b/lib/execjs/ruby_rhino_runtime.rb
@@ -7,7 +7,7 @@ module ExecJS
       end
 
       def exec(source, options = {})
-        souce = source.encode('UTF-8') if source.respond_to?(:encode)
+        source = source.encode('UTF-8') if source.respond_to?(:encode)
 
         if /\S/ =~ source
           eval "(function(){#{source}})()", options
@@ -15,7 +15,7 @@ module ExecJS
       end
 
       def eval(source, options = {})
-        souce = source.encode('UTF-8') if source.respond_to?(:encode)
+        source = source.encode('UTF-8') if source.respond_to?(:encode)
 
         if /\S/ =~ source
           unbox @rhino_context.eval("(#{source})")