diff --git a/integration-tests-definitions/todo-lists.yaml b/integration-tests-definitions/todo-lists.yaml
index 7bc1f10b4..6146e6e8b 100644
--- a/integration-tests-definitions/todo-lists.yaml
+++ b/integration-tests-definitions/todo-lists.yaml
@@ -198,6 +198,7 @@ paths:
     parameters:
       - name: id
         in: path
+        required: true
         schema:
           type: string
     put:
diff --git a/integration-tests/typescript-express/src/generated/todo-lists.yaml/generated.ts b/integration-tests/typescript-express/src/generated/todo-lists.yaml/generated.ts
index 6b508e4f3..9c68b8cbf 100644
--- a/integration-tests/typescript-express/src/generated/todo-lists.yaml/generated.ts
+++ b/integration-tests/typescript-express/src/generated/todo-lists.yaml/generated.ts
@@ -607,7 +607,7 @@ export function createRouter(
     },
   )
 
-  const replaceAttachmentParamSchema = z.object({id: z.string().optional()})
+  const replaceAttachmentParamSchema = z.object({id: z.string()})
 
   const replaceAttachmentResponseBodyValidator = responseValidationFactory(
     [["202", z.undefined()]],
diff --git a/integration-tests/typescript-express/src/generated/todo-lists.yaml/models.ts b/integration-tests/typescript-express/src/generated/todo-lists.yaml/models.ts
index 3b6579785..b52e29b1b 100644
--- a/integration-tests/typescript-express/src/generated/todo-lists.yaml/models.ts
+++ b/integration-tests/typescript-express/src/generated/todo-lists.yaml/models.ts
@@ -53,7 +53,7 @@ export type t_GetTodoListsQuerySchema = {
 }
 
 export type t_ReplaceAttachmentParamSchema = {
-  id?: string | undefined
+  id: string
 }
 
 export type t_UpdateTodoListByIdParamSchema = {
diff --git a/integration-tests/typescript-koa/src/generated/todo-lists.yaml/generated.ts b/integration-tests/typescript-koa/src/generated/todo-lists.yaml/generated.ts
index 31ab76033..9a4caefa9 100644
--- a/integration-tests/typescript-koa/src/generated/todo-lists.yaml/generated.ts
+++ b/integration-tests/typescript-koa/src/generated/todo-lists.yaml/generated.ts
@@ -564,7 +564,7 @@ export function createRouter(
       .then(handleResponse(ctx, uploadAttachmentResponseValidator))
   })
 
-  const replaceAttachmentParamSchema = z.object({id: z.string().optional()})
+  const replaceAttachmentParamSchema = z.object({id: z.string()})
 
   const replaceAttachmentResponseValidator = responseValidationFactory(
     [["202", z.undefined()]],
diff --git a/integration-tests/typescript-koa/src/generated/todo-lists.yaml/models.ts b/integration-tests/typescript-koa/src/generated/todo-lists.yaml/models.ts
index 724d4ac33..8633abcde 100644
--- a/integration-tests/typescript-koa/src/generated/todo-lists.yaml/models.ts
+++ b/integration-tests/typescript-koa/src/generated/todo-lists.yaml/models.ts
@@ -53,7 +53,7 @@ export type t_GetTodoListsQuerySchema = {
 }
 
 export type t_ReplaceAttachmentParamSchema = {
-  id?: string
+  id: string
 }
 
 export type t_UpdateTodoListByIdParamSchema = {
diff --git a/packages/openapi-code-generator/src/core/normalization/parameter-normalizer.spec.ts b/packages/openapi-code-generator/src/core/normalization/parameter-normalizer.spec.ts
index c7aed5d00..1f3166c05 100644
--- a/packages/openapi-code-generator/src/core/normalization/parameter-normalizer.spec.ts
+++ b/packages/openapi-code-generator/src/core/normalization/parameter-normalizer.spec.ts
@@ -102,6 +102,19 @@ describe("ParameterNormalizer", () => {
           }),
         ).toThrow("unsupported parameter style: 'form' for in: 'path'")
       })
+
+      it("forces required=true", () => {
+        expect(
+          parameterNormalizer.normalizeParameter({
+            name: "id",
+            in: "path",
+            required: false,
+            schema: {type: "string"},
+          }),
+        ).toStrictEqual(
+          ir.pathParameter({style: "simple", explode: false, required: true}),
+        )
+      })
     })
 
     describe("query parameters", () => {
diff --git a/packages/openapi-code-generator/src/core/normalization/parameter-normalizer.ts b/packages/openapi-code-generator/src/core/normalization/parameter-normalizer.ts
index 8d0962ba8..befa35d1d 100644
--- a/packages/openapi-code-generator/src/core/normalization/parameter-normalizer.ts
+++ b/packages/openapi-code-generator/src/core/normalization/parameter-normalizer.ts
@@ -117,7 +117,7 @@ export class ParameterNormalizer {
 
       properties[parameter.name] = schema
 
-      if (parameter.required) {
+      if (parameter.required || parameter.in === "path") {
         required.push(parameter.name)
       }
     }