diff --git a/lib/uri.ml b/lib/uri.ml
index 02f93dd..e1e0155 100644
--- a/lib/uri.ml
+++ b/lib/uri.ml
@@ -104,6 +104,7 @@ module Generic : Scheme = struct
     (* '&' is safe but we should encode literals to avoid ambiguity
        with the already parsed qs params *)
     a.(Char.code '&') <- false;
+    a.(Char.code ';') <- false;
     a.(Char.code '+') <- false;
     a
 
diff --git a/lib_test/test_runner.ml b/lib_test/test_runner.ml
index 79a6328..229cb1a 100644
--- a/lib_test/test_runner.ml
+++ b/lib_test/test_runner.ml
@@ -135,6 +135,8 @@ let uri_query_make = [
   ["foo1",["bar1"];"foo2",["bar2"]], "foo1=bar1&foo2=bar2";
   ["foo1",["bar1"];"foo2",["bar2"];"foo3",["bar3"]],
   "foo1=bar1&foo2=bar2&foo3=bar3";
+  ["semicolon",[";"]],"semicolon=%3B";
+  [";",["semicolon"]],"%3B=semicolon";
   ["#",["#";"#"]], "%23=%23,%23";
   ["",[]], "";
   ["",[""]], "=";