diff --git a/lib/oauth2/client.rb b/lib/oauth2/client.rb
index bffd9cca1179a3a2ad1d1c7dc7a2ae1270299ed3..104d2b9c0a11f6dee254b22a660c95254d15b81e 100644
--- a/lib/oauth2/client.rb
+++ b/lib/oauth2/client.rb
@@ -3,6 +3,8 @@
 require 'faraday'
 require 'logger'
 
+Faraday::Utils.default_space_encoding = '%20'
+
 module OAuth2
   ConnectionError = Class.new(Faraday::ConnectionFailed)
   TimeoutError = Class.new(Faraday::TimeoutError)
diff --git a/spec/oauth2/client_spec.rb b/spec/oauth2/client_spec.rb
index 57539b1b0f48adb3e013ab52718d64a42f63f18a..a889f8e2ca49df7cab068dd4aaf1633cb1fc2297 100644
--- a/spec/oauth2/client_spec.rb
+++ b/spec/oauth2/client_spec.rb
@@ -318,6 +318,20 @@ RSpec.describe OAuth2::Client do
     end
   end
 
+  describe '#authorize_url' do
+    subject { instance.authorize_url(params) }
+
+    context 'when space included' do
+      let(:params) do
+        { scope: 'email profile' }
+      end
+
+      it 'encoded as %20' do
+        expect(subject).to include 'email%20profile'
+      end
+    end
+  end
+
   describe '#request' do
     it 'works with a null response body' do
       expect(subject.request(:get, 'empty_get').body).to eq('')