diff --git a/core/modules/entity_reference/config/schema/entity_reference.schema.yml b/core/modules/entity_reference/config/schema/entity_reference.schema.yml
index eb9bd15..2f992ab 100644
--- a/core/modules/entity_reference/config/schema/entity_reference.schema.yml
+++ b/core/modules/entity_reference/config/schema/entity_reference.schema.yml
@@ -35,9 +35,6 @@ field.entity_reference.instance_settings:
             direction:
               type: string
               label: 'Sort direction'
-    user_register_form:
-      type: boolean
-      label: 'Display on user registration form.'
 
 field.entity_reference.value:
   type: sequence