diff --git a/lib/omniauth.rb b/lib/omniauth.rb
index dc315ee..f9cfaf8 100644
--- a/lib/omniauth.rb
+++ b/lib/omniauth.rb
@@ -159,7 +159,7 @@ module OmniAuth
       if first_letter_in_uppercase
         word.to_s.gsub(%r{/(.?)}) { '::' + Regexp.last_match[1].upcase }.gsub(/(^|_)(.)/) { Regexp.last_match[2].upcase }
       else
-        word.first + camelize(word)[1..-1]
+        camelize(word).tap { |w| w[0] = w[0].downcase }
       end
     end
   end
diff --git a/spec/omniauth_spec.rb b/spec/omniauth_spec.rb
index 12f3161..8013ccb 100644
--- a/spec/omniauth_spec.rb
+++ b/spec/omniauth_spec.rb
@@ -148,6 +148,10 @@ describe OmniAuth do
         OmniAuth.config.add_camelization('oauth', 'OAuth')
         expect(OmniAuth::Utils.camelize(:oauth)).to eq('OAuth')
       end
+
+      it 'doesn\'t uppercase the first letter when passed false' do
+        expect(OmniAuth::Utils.camelize('apple_jack', false)).to eq('appleJack')
+      end
     end
   end
 end