diff --git a/administrator/components/com_fields/src/Model/FieldModel.php b/administrator/components/com_fields/src/Model/FieldModel.php
index b1318736ee1fa..16f13c537d4f1 100644
--- a/administrator/components/com_fields/src/Model/FieldModel.php
+++ b/administrator/components/com_fields/src/Model/FieldModel.php
@@ -1005,6 +1005,21 @@ protected function loadFormData()
      */
     public function validate($form, $data, $group = null)
     {
+        // Check if the values are unique. This should only apply for list, checkboxes and radio custom field types
+        if (\in_array($data['type'], ['list', 'checkboxes', 'radio'])
+            && !empty($data['fieldparams']['options'])
+            && \is_array($data['fieldparams']['options'])) {
+            $tmpValues = [];
+            foreach ($data['fieldparams']['options'] as $option) {
+                $tmpValues[] = $option['value'];
+            }
+
+            if (\count($tmpValues) !== \count(array_unique($tmpValues))) {
+                Factory::getApplication()->enqueueMessage(Text::_('COM_FIELDS_FIELD_INVALID_DUPLICATE_VALUES'), 'error');
+
+                return false;
+            }
+        }
         if (!$this->getCurrentUser()->authorise('core.admin', 'com_fields')) {
             if (isset($data['rules'])) {
                 unset($data['rules']);
diff --git a/administrator/language/en-GB/com_fields.ini b/administrator/language/en-GB/com_fields.ini
index ca7ab9f4c122c..c0f2cfb728451 100644
--- a/administrator/language/en-GB/com_fields.ini
+++ b/administrator/language/en-GB/com_fields.ini
@@ -31,6 +31,7 @@ COM_FIELDS_FIELD_IMAGE_ALT_LABEL="Alt Text"
 COM_FIELDS_FIELD_IMAGE_DESC="Image label."
 COM_FIELDS_FIELD_IMAGE_LABEL="Image"
 COM_FIELDS_FIELD_INVALID_DEFAULT_VALUE="The default value is invalid."
+COM_FIELDS_FIELD_INVALID_DUPLICATE_VALUES="The option values must be unique."
 COM_FIELDS_FIELD_LABEL_FORM_CLASS_LABEL="Label Class (Form)"
 COM_FIELDS_FIELD_LABEL_LABEL="Label"
 COM_FIELDS_FIELD_LABEL_RENDER_CLASS_LABEL="Label Class (Output)"