diff --git a/client/html/post_upload_row.tpl b/client/html/post_upload_row.tpl
index c7cc5dba..2885e3d7 100644
--- a/client/html/post_upload_row.tpl
+++ b/client/html/post_upload_row.tpl
@@ -61,6 +61,7 @@
                             text: 'Upload anonymously',
                             name: 'anonymous',
                             checked: ctx.uploadable.anonymous,
+                            readonly: ctx.uploadable.forceAnonymous,
                         }) %>
                     </div>
                 <% } %>
diff --git a/client/js/views/post_upload_view.js b/client/js/views/post_upload_view.js
index b92a9aef..7fdd4a4f 100644
--- a/client/js/views/post_upload_view.js
+++ b/client/js/views/post_upload_view.js
@@ -1,6 +1,7 @@
 "use strict";
 
 const events = require("../events.js");
+const api = require("../api.js");
 const views = require("../util/views.js");
 const FileDropperControl = require("../controls/file_dropper_control.js");
 
@@ -34,7 +35,8 @@ class Uploadable extends events.EventTarget {
         this.flags = [];
         this.tags = [];
         this.relations = [];
-        this.anonymous = false;
+        this.anonymous = !api.isLoggedIn();
+        this.forceAnonymous = !api.isLoggedIn();
     }
 
     destroy() {}