diff --git a/lib/puma/server.rb b/lib/puma/server.rb
index 17290117..4c102b3e 100644
--- a/lib/puma/server.rb
+++ b/lib/puma/server.rb
@@ -522,7 +522,9 @@ module Puma
 
         raise "No REQUEST PATH" unless env[REQUEST_PATH]
 
-        env[QUERY_STRING] = uri.query
+        # A nil env value will cause a LintError (and fatal errors elsewhere),
+        # so only set the env value if there actually is a value.
+        env[QUERY_STRING] = uri.query if uri.query
       end
 
       env[PATH_INFO] = env[REQUEST_PATH]