diff --git a/activestorage/CHANGELOG.md b/activestorage/CHANGELOG.md
index eb343a3240..0d67955185 100644
--- a/activestorage/CHANGELOG.md
+++ b/activestorage/CHANGELOG.md
@@ -1,3 +1,9 @@
+*   Attachments can be deleted after their association is no longer defined.
+
+    Fixes #42514
+
+    *Don Sisco*
+
 *   Allow to detach an attachment when record is not persisted
 
     *Jacopo Beschi*
diff --git a/activestorage/app/models/active_storage/attachment.rb b/activestorage/app/models/active_storage/attachment.rb
index 6e8dcac906..c0a8d787b2 100644
--- a/activestorage/app/models/active_storage/attachment.rb
+++ b/activestorage/app/models/active_storage/attachment.rb
@@ -74,7 +74,7 @@ class ActiveStorage::Attachment < ActiveStorage::Record
     end
 
     def dependent
-      record.attachment_reflections[name]&.options[:dependent]
+      record.attachment_reflections[name]&.options&.fetch(:dependent, nil)
     end
 
     def variants
diff --git a/activestorage/test/models/attachment_test.rb b/activestorage/test/models/attachment_test.rb
index c675b96559..66c973c502 100644
--- a/activestorage/test/models/attachment_test.rb
+++ b/activestorage/test/models/attachment_test.rb
@@ -134,6 +134,14 @@ class ActiveStorage::AttachmentTest < ActiveSupport::TestCase
     assert_equal blob, ActiveStorage::Blob.find_signed(signed_id)
   end
 
+  test "can destroy attachment without existing relation" do
+    blob = create_blob
+    @user.highlights.attach(blob)
+    attachment = @user.highlights.find_by(blob_id: blob.id)
+    attachment.update_attribute(:name, "old_highlights")
+    assert_nothing_raised { attachment.destroy }
+  end
+
   private
     def assert_blob_identified_before_owner_validated(owner, blob, content_type)
       validated_content_type = nil