diff --git a/inputfiles/patches/html-autocomplete.kdl b/inputfiles/patches/html-autocomplete.kdl
index 986541bcb..f6d634849 100644
--- a/inputfiles/patches/html-autocomplete.kdl
+++ b/inputfiles/patches/html-autocomplete.kdl
@@ -74,9 +74,9 @@ enum AutoFillCredentialField {
 }
 
 typedef OptionalPrefixToken overrideType=#"`${T} ` | """# {
-  typeParameters T extends=string
+  typeParameter T extends=string
 }
 
 typedef OptionalPostfixToken overrideType=#"` ${T}` | """# {
-  typeParameters T extends=string
+  typeParameter T extends=string
 }
diff --git a/inputfiles/patches/html.kdl b/inputfiles/patches/html.kdl
index dd2e5676d..6420bce45 100644
--- a/inputfiles/patches/html.kdl
+++ b/inputfiles/patches/html.kdl
@@ -60,7 +60,7 @@ interface HTMLProgressElement {
   }
 }
 
-interface-mixin MessageEventTarget overrideThis=T typeParameters=T
+interface-mixin MessageEventTarget overrideThis=T typeParameter=T
 
 interface-mixin WindowEventHandlers {
   property onunload deprecated="The unload event is not reliable, consider visibilitychange or pagehide events."
diff --git a/inputfiles/patches/indexeddb.kdl b/inputfiles/patches/indexeddb.kdl
index 02a0fba2d..c8ce251fd 100644
--- a/inputfiles/patches/indexeddb.kdl
+++ b/inputfiles/patches/indexeddb.kdl
@@ -1,5 +1,5 @@
 interface IDBRequest {
-   typeParameters T default=any
+   typeParameter T default=any
    property source {
       type nullable=#false
    }
diff --git a/inputfiles/patches/readable-stream.kdl b/inputfiles/patches/readable-stream.kdl
index e56076039..f475278c7 100644
--- a/inputfiles/patches/readable-stream.kdl
+++ b/inputfiles/patches/readable-stream.kdl
@@ -1,15 +1,15 @@
-dictionary ReadableStreamReadDoneResult typeParameters=T {
+dictionary ReadableStreamReadDoneResult typeParameter=T {
     member done required=#true overrideType="true"
     member value required=#true overrideType="T | undefined"
 }
 
-dictionary ReadableStreamReadValueResult typeParameters=T {
+dictionary ReadableStreamReadValueResult typeParameter=T {
     member done required=#true overrideType="false"
     member value required=#true overrideType="T"
 }
 
 dictionary UnderlyingSource {
-    typeParameters R default=any
+    typeParameter R default=any
     member start overrideType="UnderlyingSourceStartCallback<R>"
     member pull overrideType="UnderlyingSourcePullCallback<R>"
 }
diff --git a/inputfiles/patches/streams.kdl b/inputfiles/patches/streams.kdl
index 3fd8228e7..b1cc50f1c 100644
--- a/inputfiles/patches/streams.kdl
+++ b/inputfiles/patches/streams.kdl
@@ -1,7 +1,7 @@
 // https://streams.spec.whatwg.org/#dictdef-underlyingsource
 
 dictionary UnderlyingDefaultSource {
-  typeParameters R default=any
+  typeParameter R default=any
   member type type=undefined
   member start overrideType="(controller: ReadableStreamDefaultController<R>) => any"
   member pull overrideType="(controller: ReadableStreamDefaultController<R>) => void | PromiseLike<void>"
diff --git a/src/build/patches.ts b/src/build/patches.ts
index ac72d1742..f4c381204 100644
--- a/src/build/patches.ts
+++ b/src/build/patches.ts
@@ -91,25 +91,27 @@ function handleTyped(
   return types[0];
 }
 
-function handleTypeParameters(value: Value | Node) {
-  if (!value) {
-    return {};
-  }
-  if (typeof value === "string") {
-    return { typeParameters: [{ name: value }] };
-  }
-  const node = value as Node;
+function handleSingleTypeParameterNode(node: Node) {
   return {
-    typeParameters: [
-      {
-        name: string(node.values[0]),
-        ...optionalMember("default", "string", node.properties?.default),
-        ...optionalMember("extends", "string", node.properties?.extends),
-      },
-    ],
+    name: string(node.values[0]),
+    ...optionalMember("default", "string", node.properties?.default),
+    ...optionalMember("extends", "string", node.properties?.extends),
   };
 }
 
+function handleTypeParameter(node: Node[], property?: Value) {
+  let typeParameters: any;
+  if (typeof property === "string") {
+    typeParameters = [{ name: property }];
+  } else {
+    typeParameters = node.map(handleSingleTypeParameterNode);
+  }
+  if (!typeParameters || typeParameters.length === 0) {
+    return {};
+  }
+  return { typeParameters };
+}
+
 function optionalNestedMember<T>(prop: string, object: object, output: T) {
   return Object.entries(object).length ? { [prop]: output } : {};
 }
@@ -207,7 +209,7 @@ function handleMixinAndInterfaces(
   const property: Record<string, DeepPartial<Property>> = {};
   let method: Record<string, DeepPartial<OverridableMethod>> = {};
   let constructor: DeepPartial<OverridableMethod> | undefined;
-  let typeParameters = {};
+  const typeParameter = [];
 
   for (const child of node.children) {
     switch (child.name) {
@@ -232,8 +234,8 @@ function handleMixinAndInterfaces(
         constructor = merge(constructor, c);
         break;
       }
-      case "typeParameters": {
-        typeParameters = handleTypeParameters(child);
+      case "typeParameter": {
+        typeParameter.push(child);
         break;
       }
       default:
@@ -242,7 +244,6 @@ function handleMixinAndInterfaces(
   }
 
   const interfaceObject = type === "interface" && {
-    ...typeParameters,
     ...(constructor ? { constructor } : {}),
     ...optionalMember("exposed", "string", node.properties?.exposed),
     ...optionalMember("deprecated", "string", node.properties?.deprecated),
@@ -270,7 +271,7 @@ function handleMixinAndInterfaces(
       "string",
       node.properties?.replaceReference,
     ),
-    ...handleTypeParameters(node.properties?.typeParameters),
+    ...handleTypeParameter(typeParameter, node.properties?.typeParameter),
     ...interfaceObject,
   } as DeepPartial<Interface>;
 }
@@ -396,7 +397,7 @@ function handleMethodAndConstructor(
 function handleDictionary(child: Node): DeepPartial<Dictionary> {
   const name = string(child.values[0]);
   const member: Record<string, DeepPartial<Member>> = {};
-  let typeParameters = {};
+  const typeParameter = [];
 
   for (const c of child.children) {
     switch (c.name) {
@@ -405,8 +406,8 @@ function handleDictionary(child: Node): DeepPartial<Dictionary> {
         member[memberName] = handleMember(c);
         break;
       }
-      case "typeParameters": {
-        typeParameters = handleTypeParameters(c);
+      case "typeParameter": {
+        typeParameter.push(c);
         break;
       }
       default:
@@ -417,8 +418,7 @@ function handleDictionary(child: Node): DeepPartial<Dictionary> {
   return {
     name,
     members: { member },
-    ...typeParameters,
-    ...handleTypeParameters(child.properties?.typeParameters),
+    ...handleTypeParameter(typeParameter, child.properties?.typeParameter),
     ...optionalMember(
       "legacyNamespace",
       "string",
@@ -450,14 +450,14 @@ function handleMember(c: Node): DeepPartial<Member> {
  */
 function handleTypedef(node: Node): DeepPartial<TypeDef> {
   const typeNodes: Node[] = [];
-  let typeParameters = {};
+  const typeParameter = [];
   for (const child of node.children) {
     switch (child.name) {
       case "type":
         typeNodes.push(child);
         break;
-      case "typeParameters": {
-        typeParameters = handleTypeParameters(child);
+      case "typeParameter": {
+        typeParameter.push(child);
         break;
       }
       default:
@@ -475,7 +475,7 @@ function handleTypedef(node: Node): DeepPartial<TypeDef> {
       node.properties?.legacyNamespace,
     ),
     ...optionalMember("overrideType", "string", node.properties?.overrideType),
-    ...typeParameters,
+    ...handleTypeParameter(typeParameter, node.properties?.typeParameter),
   };
 }