diff --git a/packages/extension-subscript/src/subscript.ts b/packages/extension-subscript/src/subscript.ts
index 06636207..09d4e6cd 100644
--- a/packages/extension-subscript/src/subscript.ts
+++ b/packages/extension-subscript/src/subscript.ts
@@ -30,6 +30,8 @@ export const Subscript = Mark.create<SubscriptExtensionOptions>({
     HTMLAttributes: {},
   },
 
+  excludes: 'superscript',
+
   parseHTML() {
     return [
       {
diff --git a/packages/extension-superscript/src/superscript.ts b/packages/extension-superscript/src/superscript.ts
index 26a348aa..adf6a930 100644
--- a/packages/extension-superscript/src/superscript.ts
+++ b/packages/extension-superscript/src/superscript.ts
@@ -30,6 +30,8 @@ export const Superscript = Mark.create<SuperscriptExtensionOptions>({
     HTMLAttributes: {},
   },
 
+  excludes: 'subscript',
+
   parseHTML() {
     return [
       {