diff --git a/lib/compiler/Maker.zig b/lib/compiler/Maker.zig
index e3aefb00343062a9e576e227e1e0a98e04c43f46..dbb40ec694cd1e0914a6c3688ee4f0307e1efd3b 100644
--- a/lib/compiler/Maker.zig
+++ b/lib/compiler/Maker.zig
@@ -682,6 +682,7 @@ pub fn main(init: process.Init.Minimal) !void {
 
     var web_server_allocation: AvoidableWebServer = undefined;
     const web_server: ?*AvoidableWebServer = if (webui_listen) |listen_address| ws: {
+        if (watch) fatal("using '--webui' and '--watch' together is not yet supported; consider omitting '--watch' in favour of the web UI \"Rebuild\" button", .{});
         if (builtin.single_threaded) fatal("--webui is not yet supported on single-threaded hosts", .{});
         web_server_allocation = .init(.{
             .graph = &graph,