diff --git a/src/ngx_pagespeed.cc b/src/ngx_pagespeed.cc
index 4ef079282..7e917f3ae 100644
--- a/src/ngx_pagespeed.cc
+++ b/src/ngx_pagespeed.cc
@@ -1903,6 +1903,11 @@ ngx_int_t ps_resource_handler(ngx_http_request_t* r,
           custom_options.release(), ctx->base_fetch->request_context());
     }
 
+    StringPiece user_agent = ctx->base_fetch->request_headers()->Lookup1(
+        HttpAttributes::kUserAgent);
+    if (!user_agent.empty()) {
+      driver->SetUserAgent(user_agent);
+    }
     driver->SetRequestHeaders(*ctx->base_fetch->request_headers());
     driver->set_pagespeed_query_params(pagespeed_query_params);
     driver->set_pagespeed_option_cookies(pagespeed_option_cookies);
@@ -1943,7 +1948,13 @@ ngx_int_t ps_resource_handler(ngx_http_request_t* r,
           custom_options.release(), ctx->base_fetch->request_context());
     }
 
+    StringPiece user_agent = ctx->base_fetch->request_headers()->Lookup1(
+        HttpAttributes::kUserAgent);
+    if (!user_agent.empty()) {
+      driver->SetUserAgent(user_agent);
+    }
     driver->SetRequestHeaders(*ctx->base_fetch->request_headers());
+
     ctx->driver = driver;
 
     cfg_s->server_context->message_handler()->Message(