diff --git a/packages/generator/src/generation/model/components/Parameters.ts b/packages/generator/src/generation/model/components/Parameters.ts
index 0b6f3581..3d58edee 100644
--- a/packages/generator/src/generation/model/components/Parameters.ts
+++ b/packages/generator/src/generation/model/components/Parameters.ts
@@ -4,6 +4,7 @@ import { Components, ComponentType } from "./Components.js";
 import { asyncStringJoin } from "../../asyncStringJoin.js";
 import { TypeCompilationOptions } from "../CodeGenerationModel.js";
 import { assertNoRefs } from "../../refs/assertNoRefs.js";
+import { populateNullableTypes } from "../../populateNullableTypes.js";
 
 export class Parameters {
   public static readonly ns = "Parameters";
@@ -24,7 +25,12 @@ export class Parameters {
   public async compileTypes(opts: TypeCompilationOptions): Promise<string> {
     const schemas = Object.entries(this.parameters).map(([name, param]) => {
       assertNoRefs(param);
-      return new JSONSchema(new Name(name, this.name), param.schema);
+      return new JSONSchema(
+        new Name(name, this.name),
+        param.schema !== undefined
+          ? populateNullableTypes(param.schema)
+          : undefined,
+      );
     });
 
     const t = {
diff --git a/packages/generator/src/generation/model/components/RequestBodies.ts b/packages/generator/src/generation/model/components/RequestBodies.ts
index ccb1c8f0..f412ee65 100644
--- a/packages/generator/src/generation/model/components/RequestBodies.ts
+++ b/packages/generator/src/generation/model/components/RequestBodies.ts
@@ -4,6 +4,7 @@ import { Components } from "./Components.js";
 import { asyncStringJoin } from "../../asyncStringJoin.js";
 import { TypeCompilationOptions } from "../CodeGenerationModel.js";
 import { OpenAPIV3 } from "openapi-types";
+import { populateNullableTypesForRequestBody } from "../../populateNullableTypes.js";
 
 export class RequestBodies {
   public static readonly ns = "RequestBodies";
@@ -20,7 +21,10 @@ export class RequestBodies {
     this.name = new Name(RequestBodies.ns, components.name);
     this.schemas = Object.entries(schemas ?? {}).map(
       ([schemaName, schema]) =>
-        new JSONSchema(new Name(schemaName, this.name), schema),
+        new JSONSchema(
+          new Name(schemaName, this.name),
+          populateNullableTypesForRequestBody(schema),
+        ),
     );
   }
 
diff --git a/packages/generator/src/generation/model/components/Response.ts b/packages/generator/src/generation/model/components/Response.ts
index 6f7c5c41..5a0b4a69 100644
--- a/packages/generator/src/generation/model/components/Response.ts
+++ b/packages/generator/src/generation/model/components/Response.ts
@@ -5,6 +5,7 @@ import { Responses } from "./Responses.js";
 import { TypeCompilationOptions } from "../CodeGenerationModel.js";
 import { OpenAPIV3 } from "openapi-types";
 import invariant from "invariant";
+import { populateNullableTypes } from "../../populateNullableTypes.js";
 
 export class Response {
   public readonly name: Name;
@@ -21,7 +22,13 @@ export class Response {
     this.contents = Object.entries(mediaTypesDoc).map(
       ([mediaType, mediaTypeObj]) => {
         invariant(!!mediaTypeObj?.schema, "No schema set");
-        return new ResponseContent(this, mediaType, mediaTypeObj?.schema);
+        return new ResponseContent(
+          this,
+          mediaType,
+          mediaTypeObj?.schema
+            ? populateNullableTypes(mediaTypeObj.schema)
+            : mediaTypeObj.schema,
+        );
       },
     );
   }
diff --git a/packages/generator/src/generation/model/paths/Path.ts b/packages/generator/src/generation/model/paths/Path.ts
index 848f870a..13061280 100644
--- a/packages/generator/src/generation/model/paths/Path.ts
+++ b/packages/generator/src/generation/model/paths/Path.ts
@@ -4,6 +4,7 @@ import { asyncStringJoin } from "../../asyncStringJoin.js";
 import { Paths } from "./Paths.js";
 import { TypeCompilationOptions } from "../CodeGenerationModel.js";
 import { OpenAPIV3 } from "openapi-types";
+import { populateNullableTypesForPathItem } from "../../populateNullableTypes.js";
 
 export class Path {
   public readonly paths: Paths;
@@ -31,7 +32,11 @@ export class Path {
     name: string,
     operationsDoc: OpenAPIV3.PathItemObject,
   ) {
-    return new Path(paths, new Name(name, paths.name), operationsDoc);
+    return new Path(
+      paths,
+      new Name(name, paths.name),
+      populateNullableTypesForPathItem(operationsDoc),
+    );
   }
 
   public async compileTypes(options: TypeCompilationOptions): Promise<string> {
diff --git a/packages/generator/src/generation/populateNullableTypes.ts b/packages/generator/src/generation/populateNullableTypes.ts
index 46050a2e..da3fefcc 100644
--- a/packages/generator/src/generation/populateNullableTypes.ts
+++ b/packages/generator/src/generation/populateNullableTypes.ts
@@ -18,7 +18,6 @@ export function populateNullableTypes(
   }
 
   const compositionKeys = ["allOf", "anyOf", "oneOf"] as const;
-
   compositionKeys.forEach((key) => {
     const entries = schema[key];
     if (Array.isArray(entries)) {
@@ -27,10 +26,88 @@ export function populateNullableTypes(
   });
 
   if (schema.nullable) {
+    const { nullable: ignoredNullable, ...schemaWithoutNullable } = schema;
     return {
-      anyOf: [schema, { type: "null" } as unknown as OpenAPIV3.SchemaObject],
+      anyOf: [
+        schemaWithoutNullable as OpenAPIV3.SchemaObject,
+        { type: "null" } as unknown as OpenAPIV3.SchemaObject,
+      ],
     };
   }
 
   return schema;
 }
+
+export function populateNullableTypesForRequestBody(
+  requestBody: OpenAPIV3.ReferenceObject | OpenAPIV3.RequestBodyObject,
+): OpenAPIV3.ReferenceObject | OpenAPIV3.RequestBodyObject {
+  if (!requestBody || "$ref" in requestBody) {
+    return requestBody;
+  }
+  for (const mediaType in requestBody.content) {
+    const mediaTypeObject = requestBody.content[mediaType];
+    if (mediaTypeObject?.schema) {
+      mediaTypeObject.schema = populateNullableTypes(mediaTypeObject.schema);
+    }
+  }
+  return requestBody;
+}
+
+export function populateNullableTypesForResponse(
+  response: OpenAPIV3.ReferenceObject | OpenAPIV3.ResponseObject,
+): OpenAPIV3.ReferenceObject | OpenAPIV3.ResponseObject {
+  if (!response || "$ref" in response) {
+    return response;
+  }
+  if (response.content) {
+    for (const mediaType in response.content) {
+      const mediaTypeObject = response.content[mediaType];
+      if (mediaTypeObject?.schema) {
+        mediaTypeObject.schema = populateNullableTypes(mediaTypeObject.schema);
+      }
+    }
+  }
+  return response;
+}
+
+export function populateNullableTypesForPathItem(
+  pathItem: OpenAPIV3.ReferenceObject | OpenAPIV3.PathItemObject,
+): OpenAPIV3.ReferenceObject | OpenAPIV3.PathItemObject {
+  if (!pathItem || "$ref" in pathItem) {
+    return pathItem;
+  }
+
+  for (const httpMethod of Object.values(OpenAPIV3.HttpMethods)) {
+    const operation = pathItem[httpMethod];
+
+    if (!operation) {
+      continue;
+    }
+
+    if (operation.parameters) {
+      operation.parameters.forEach((param) => {
+        if (param && !("$ref" in param) && param.schema) {
+          param.schema = populateNullableTypes(param.schema);
+        }
+      });
+    }
+
+    if (operation.requestBody) {
+      operation.requestBody = populateNullableTypesForRequestBody(
+        operation.requestBody,
+      );
+    }
+
+    if (operation.responses) {
+      for (const statusCode in operation.responses) {
+        const response = operation.responses[statusCode];
+        if (response) {
+          operation.responses[statusCode] =
+            populateNullableTypesForResponse(response);
+        }
+      }
+    }
+  }
+
+  return pathItem;
+}