diff --git a/Gemfile.lock b/Gemfile.lock
index 85a6a46f..e1c67654 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -436,6 +436,7 @@ PLATFORMS
   arm64-darwin-22
   x86_64-darwin-19
   x86_64-darwin-20
+  x86_64-darwin-21
   x86_64-linux
 
 DEPENDENCIES
diff --git a/app/assets/javascripts/edit_assessment.js b/app/assets/javascripts/edit_assessment.js
index d669cf2c..f15374e3 100644
--- a/app/assets/javascripts/edit_assessment.js
+++ b/app/assets/javascripts/edit_assessment.js
@@ -32,6 +32,17 @@
       changes = false;
     });
 
+    $('#assessment_config_file').on('change', function () {
+      var fileSelector = $("#assessment_config_file").get(0);
+      var file = fileSelector.files[0];
+
+      if (!file?.name?.endsWith('.rb')) {
+        $('#config-file-type-incorrect').text(`Warning: ${file.name} doesn't match expected .rb file type`)
+      } else {
+        $('#config-file-type-incorrect').text("")
+      }
+    })
+
     $('input[name="assessment[is_positive_grading]"]').on('change', function() {
       if(has_annotations){
         if ($(this).prop('checked') !=  is_positive_grading) {
diff --git a/app/views/assessments/_edit_basic.html.erb b/app/views/assessments/_edit_basic.html.erb
index e2bd3c21..b32bdace 100755
--- a/app/views/assessments/_edit_basic.html.erb
+++ b/app/views/assessments/_edit_basic.html.erb
@@ -32,6 +32,7 @@
 <%= f.file_field :config_file, button_text: "Upload #{@assessment.name}.rb",
                                help_text: "Config file will be automatically reloaded after saving. Changes to other settings will
                  be lost if an error is encountered." %>
+<b id="config-file-type-incorrect" style="color: red; margin: 0"></b>
 
 <h4>Modules Used</h4>
 <ul class="collection attachments">