diff --git a/baselines/dom.generated.d.ts b/baselines/dom.generated.d.ts
index c9f4e278b..eb8a3a590 100644
--- a/baselines/dom.generated.d.ts
+++ b/baselines/dom.generated.d.ts
@@ -6244,6 +6244,7 @@ interface HTMLFormElement extends HTMLElement {
     removeEventListener<K extends keyof HTMLElementEventMap>(type: K, listener: (this: HTMLFormElement, ev: HTMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
     removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
     [index: number]: Element;
+    [name: string]: any;
 }
 
 declare var HTMLFormElement: {
diff --git a/inputfiles/overridingTypes.json b/inputfiles/overridingTypes.json
index 21dd19c1c..0a4d41b20 100644
--- a/inputfiles/overridingTypes.json
+++ b/inputfiles/overridingTypes.json
@@ -2297,6 +2297,12 @@
                         }
                     }
                 }
+            },
+            "HTMLFormElement": {
+                "override-index-signatures": [
+                    "[index: number]: Element",
+                    "[name: string]: any"
+                ]
             }
         }
     },