diff --git a/lib/linguist/language.rb b/lib/linguist/language.rb
index f6800315..20db7232 100644
--- a/lib/linguist/language.rb
+++ b/lib/linguist/language.rb
@@ -12,7 +12,7 @@ module Linguist
       @name_index[language.name.downcase] = language
 
       if language.default_lexer? || !@lexer_index.key?(language.lexer)
-        @lexer_index[language.lexer] = language
+        @lexer_index[language.lexer.downcase] = language
       end
 
       language.extensions.each do |extension|
@@ -24,7 +24,7 @@ module Linguist
     end
 
     def self.[](name)
-      find_by_name(name)
+      find_by_name(name) || find_by_lexer(name)
     end
 
     def self.find_by_name(name)
@@ -36,7 +36,7 @@ module Linguist
     end
 
     def self.find_by_lexer(lexer)
-      @lexer_index[lexer] || self['Text']
+      @lexer_index[lexer.downcase] || self['Text']
     end
 
     def self.popular
diff --git a/test/test_language.rb b/test/test_language.rb
index 566c1082..2fd1016e 100644
--- a/test/test_language.rb
+++ b/test/test_language.rb
@@ -28,6 +28,20 @@ class TestLanguage < Test::Unit::TestCase
     assert_equal Language['Text'], Language.find_by_lexer('kt')
   end
 
+  def test_find
+    assert_equal "Ruby", Language['Ruby'].name
+    assert_equal "Ruby", Language['ruby'].name
+    assert_equal "Ruby", Language['RUBY'].name
+    assert_equal "C++", Language['C++'].name
+    assert_equal "C++", Language['c++'].name
+    assert_equal "C++", Language['cpp'].name
+    assert_equal "C#", Language['C#'].name
+    assert_equal "C#", Language['c#'].name
+    assert_equal "C#", Language['csharp'].name
+    assert_equal "C#", Language['CSHARP'].name
+    assert_equal "Text", Language['defunkt'].name
+  end
+
   def test_name
     assert_equal "Perl",   Language['Perl'].name
     assert_equal "Python", Language['Python'].name