diff --git a/lib/travel_time/middleware/authentication.rb b/lib/travel_time/middleware/authentication.rb
index b4651b5..1c5cf15 100644
--- a/lib/travel_time/middleware/authentication.rb
+++ b/lib/travel_time/middleware/authentication.rb
@@ -14,7 +14,7 @@ class Authentication < Faraday::Middleware
       def on_request(env)
         env.request_headers[APP_ID_HEADER] = TravelTime.config.application_id
         env.request_headers[API_KEY_HEADER] = TravelTime.config.api_key
-        env.request_headers[USER_AGENT] = 'Travel Time Ruby SDK'
+        env.request_headers[USER_AGENT] = "Travel Time Ruby SDK #{TravelTime::VERSION}"
       end
     end
   end
diff --git a/lib/travel_time/version.rb b/lib/travel_time/version.rb
index 5dec5f0..9935388 100644
--- a/lib/travel_time/version.rb
+++ b/lib/travel_time/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module TravelTime
-  VERSION = '0.5.4'
+  VERSION = '0.5.5'
 end
diff --git a/spec/travel_time/middleware/authentication_spec.rb b/spec/travel_time/middleware/authentication_spec.rb
index 353b541..666c783 100644
--- a/spec/travel_time/middleware/authentication_spec.rb
+++ b/spec/travel_time/middleware/authentication_spec.rb
@@ -25,7 +25,7 @@
   it 'automatically adds User-Agent header' do
     middleware.on_request(faraday_env)
     value = faraday_env.request_headers[described_class::USER_AGENT]
-    expected = 'Travel Time Ruby SDK'
+    expected = "Travel Time Ruby SDK #{TravelTime::VERSION}"
     expect(value).to eq(expected)
   end
 end