diff --git a/src/browser/Frame.zig b/src/browser/Frame.zig
index 38e078594..237450ac3 100644
--- a/src/browser/Frame.zig
+++ b/src/browser/Frame.zig
@@ -133,6 +133,10 @@ _event_target_attr_listeners: GlobalEventHandlersLookup = .empty,
 // File objects (reference counted via their Blob proto); released at teardown.
 _file_lists: std.ArrayList(*FileList) = .empty,
 
+// List of Documents which called document.open() and potentially need to have
+// the parser freed.
+_script_created_parser_docs: std.ArrayList(*Document) = .empty,
+
 // Every matchMedia() result of this document, so a viewport change can fire
 // their `change`.
 _media_query_lists: std.ArrayList(*MediaQueryList) = .empty,
@@ -456,6 +460,16 @@ pub fn deinit(self: *Frame) void {
 
     self._parse_state.deinit(self);
 
+    for (self._script_created_parser_docs.items) |doc| {
+        const parser = &(doc._script_created_parser orelse continue);
+        if (parser.parser.frame != self) {
+            // The document was closed and re-opened on another frame
+            continue;
+        }
+        parser.deinit();
+        doc._script_created_parser = null;
+    }
+
     // Unregister CookieStore from session notifications before the JS
     // context (and thus the scheduler) is destroyed, otherwise a late
     // mutation could schedule a callback that never runs.
diff --git a/src/browser/webapi/Document.zig b/src/browser/webapi/Document.zig
index 0a283a8e2..ee95c6d91 100644
--- a/src/browser/webapi/Document.zig
+++ b/src/browser/webapi/Document.zig
@@ -1157,6 +1157,11 @@ pub fn open(self: *Document, call_frame: *Frame) !*Document {
     // gone for good, as in Chrome.
     frame.cancelQueuedNavigation();
 
+    if (std.mem.indexOfScalar(*Document, frame._script_created_parser_docs.items, self) == null) {
+        // have the page track this document (if it isn't already)
+        // so that, on shutdown, it can close the parser if needed.
+        try frame._script_created_parser_docs.append(frame.arena, self);
+    }
     self._script_created_parser = Parser.Streaming.init(frame.arena, doc_node, frame, .{ .allow_declarative_shadow = true });
     try self._script_created_parser.?.start();
     frame._parse_mode = .document;