diff --git a/packages/openapi-typescript/examples/digital-ocean-api.ts b/packages/openapi-typescript/examples/digital-ocean-api.ts
index e484f567b..c15138163 100644
--- a/packages/openapi-typescript/examples/digital-ocean-api.ts
+++ b/packages/openapi-typescript/examples/digital-ocean-api.ts
@@ -12326,7 +12326,7 @@ export interface components {
              *       "web"
              *     ]
              */
-            tags: string[];
+            tags: string[] | null;
             /**
              * @description A string containing 'user data' which may be used to configure the Droplet on first boot, often a 'cloud-config' file or Bash script. It must be plain text and may not exceed 64 KiB in size.
              * @example #cloud-config
diff --git a/packages/openapi-typescript/examples/github-api-export-type-immutable.ts b/packages/openapi-typescript/examples/github-api-export-type-immutable.ts
index 699297eb3..483598b53 100644
--- a/packages/openapi-typescript/examples/github-api-export-type-immutable.ts
+++ b/packages/openapi-typescript/examples/github-api-export-type-immutable.ts
@@ -32229,7 +32229,7 @@ export type components = {
              * @default RIGHT
              * @enum {string|null}
              */
-            readonly start_side: "LEFT" | "RIGHT";
+            readonly start_side: "LEFT" | "RIGHT" | null;
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -33004,7 +33004,7 @@ export type components = {
              * @default RIGHT
              * @enum {string|null}
              */
-            readonly start_side: "LEFT" | "RIGHT";
+            readonly start_side: "LEFT" | "RIGHT" | null;
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -108426,7 +108426,7 @@ export interface operations {
                 /** @description The name of the task for the deployment (e.g., `deploy` or `deploy:migrations`). */
                 readonly task?: string;
                 /** @description The name of the environment that was deployed to (e.g., `staging` or `production`). */
-                readonly environment?: string;
+                readonly environment?: string | null;
                 /** @description The number of results per page (max 100). For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
                 readonly per_page?: components["parameters"]["per-page"];
                 /** @description The page number of the results to fetch. For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
diff --git a/packages/openapi-typescript/examples/github-api-immutable.ts b/packages/openapi-typescript/examples/github-api-immutable.ts
index 25a97d3f9..323ea9428 100644
--- a/packages/openapi-typescript/examples/github-api-immutable.ts
+++ b/packages/openapi-typescript/examples/github-api-immutable.ts
@@ -32229,7 +32229,7 @@ export interface components {
              * @default RIGHT
              * @enum {string|null}
              */
-            readonly start_side: "LEFT" | "RIGHT";
+            readonly start_side: "LEFT" | "RIGHT" | null;
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -33004,7 +33004,7 @@ export interface components {
              * @default RIGHT
              * @enum {string|null}
              */
-            readonly start_side: "LEFT" | "RIGHT";
+            readonly start_side: "LEFT" | "RIGHT" | null;
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -108426,7 +108426,7 @@ export interface operations {
                 /** @description The name of the task for the deployment (e.g., `deploy` or `deploy:migrations`). */
                 readonly task?: string;
                 /** @description The name of the environment that was deployed to (e.g., `staging` or `production`). */
-                readonly environment?: string;
+                readonly environment?: string | null;
                 /** @description The number of results per page (max 100). For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
                 readonly per_page?: components["parameters"]["per-page"];
                 /** @description The page number of the results to fetch. For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
diff --git a/packages/openapi-typescript/examples/github-api-next.ts b/packages/openapi-typescript/examples/github-api-next.ts
index 3e54966f1..454391ea9 100644
--- a/packages/openapi-typescript/examples/github-api-next.ts
+++ b/packages/openapi-typescript/examples/github-api-next.ts
@@ -108750,7 +108750,7 @@ export interface operations {
                 /** @description The name of the task for the deployment (e.g., `deploy` or `deploy:migrations`). */
                 task?: string;
                 /** @description The name of the environment that was deployed to (e.g., `staging` or `production`). */
-                environment?: string;
+                environment?: string | null;
                 /** @description The number of results per page (max 100). For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
                 per_page?: components["parameters"]["per-page"];
                 /** @description The page number of the results to fetch. For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
diff --git a/packages/openapi-typescript/examples/github-api-required.ts b/packages/openapi-typescript/examples/github-api-required.ts
index ed8280c84..ff4362624 100644
--- a/packages/openapi-typescript/examples/github-api-required.ts
+++ b/packages/openapi-typescript/examples/github-api-required.ts
@@ -32229,7 +32229,7 @@ export interface components {
              * @default RIGHT
              * @enum {string|null}
              */
-            start_side: "LEFT" | "RIGHT";
+            start_side: "LEFT" | "RIGHT" | null;
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -33004,7 +33004,7 @@ export interface components {
              * @default RIGHT
              * @enum {string|null}
              */
-            start_side: "LEFT" | "RIGHT";
+            start_side: "LEFT" | "RIGHT" | null;
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -108426,7 +108426,7 @@ export interface operations {
                 /** @description The name of the task for the deployment (e.g., `deploy` or `deploy:migrations`). */
                 task?: string;
                 /** @description The name of the environment that was deployed to (e.g., `staging` or `production`). */
-                environment?: string;
+                environment?: string | null;
                 /** @description The number of results per page (max 100). For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
                 per_page?: components["parameters"]["per-page"];
                 /** @description The page number of the results to fetch. For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
diff --git a/packages/openapi-typescript/examples/github-api-root-types.ts b/packages/openapi-typescript/examples/github-api-root-types.ts
index f010442dc..dd0d43544 100644
--- a/packages/openapi-typescript/examples/github-api-root-types.ts
+++ b/packages/openapi-typescript/examples/github-api-root-types.ts
@@ -32229,7 +32229,7 @@ export interface components {
              * @default RIGHT
              * @enum {string|null}
              */
-            start_side: "LEFT" | "RIGHT";
+            start_side: "LEFT" | "RIGHT" | null;
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -33004,7 +33004,7 @@ export interface components {
              * @default RIGHT
              * @enum {string|null}
              */
-            start_side: "LEFT" | "RIGHT";
+            start_side: "LEFT" | "RIGHT" | null;
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -109453,7 +109453,7 @@ export interface operations {
                 /** @description The name of the task for the deployment (e.g., `deploy` or `deploy:migrations`). */
                 task?: string;
                 /** @description The name of the environment that was deployed to (e.g., `staging` or `production`). */
-                environment?: string;
+                environment?: string | null;
                 /** @description The number of results per page (max 100). For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
                 per_page?: components["parameters"]["per-page"];
                 /** @description The page number of the results to fetch. For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
diff --git a/packages/openapi-typescript/examples/github-api.ts b/packages/openapi-typescript/examples/github-api.ts
index 13489f8f8..510f78b83 100644
--- a/packages/openapi-typescript/examples/github-api.ts
+++ b/packages/openapi-typescript/examples/github-api.ts
@@ -32229,7 +32229,7 @@ export interface components {
              * @default RIGHT
              * @enum {string|null}
              */
-            start_side: "LEFT" | "RIGHT";
+            start_side: "LEFT" | "RIGHT" | null;
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -33004,7 +33004,7 @@ export interface components {
              * @default RIGHT
              * @enum {string|null}
              */
-            start_side: "LEFT" | "RIGHT";
+            start_side: "LEFT" | "RIGHT" | null;
             /**
              * @description The line of the blob to which the comment applies. The last line of the range for a multi-line comment
              * @example 2
@@ -108426,7 +108426,7 @@ export interface operations {
                 /** @description The name of the task for the deployment (e.g., `deploy` or `deploy:migrations`). */
                 task?: string;
                 /** @description The name of the environment that was deployed to (e.g., `staging` or `production`). */
-                environment?: string;
+                environment?: string | null;
                 /** @description The number of results per page (max 100). For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
                 per_page?: components["parameters"]["per-page"];
                 /** @description The page number of the results to fetch. For more information, see "[Using pagination in the REST API](https://docs.github.com/rest/using-the-rest-api/using-pagination-in-the-rest-api)." */
diff --git a/packages/openapi-typescript/src/transform/schema-object.ts b/packages/openapi-typescript/src/transform/schema-object.ts
index a41ce0e69..9f0a3b2bf 100644
--- a/packages/openapi-typescript/src/transform/schema-object.ts
+++ b/packages/openapi-typescript/src/transform/schema-object.ts
@@ -130,10 +130,7 @@ export function transformSchemaObjectWithComposition(
       return hasNull ? tsUnion([ref, NULL]) : ref;
     }
     const enumType = schemaObject.enum.map(tsLiteral);
-    if (
-      ((Array.isArray(schemaObject.type) && schemaObject.type.includes("null")) || schemaObject.nullable) &&
-      !schemaObject.default
-    ) {
+    if ((Array.isArray(schemaObject.type) && schemaObject.type.includes("null")) || schemaObject.nullable) {
       enumType.push(NULL);
     }
 
@@ -266,7 +263,7 @@ export function transformSchemaObjectWithComposition(
     }
   }
 
-  if (finalType !== UNKNOWN && schemaObject.nullable && !schemaObject.default) {
+  if (finalType !== UNKNOWN && schemaObject.nullable) {
     finalType = tsNullable([finalType]);
   }
 
@@ -405,9 +402,7 @@ function transformSchemaObjectCore(schemaObject: SchemaObject, options: Transfor
       } else {
         for (const t of schemaObject.type) {
           if (t === "null" || t === null) {
-            if (!schemaObject.default) {
-              uniqueTypes.push(NULL);
-            }
+            uniqueTypes.push(NULL);
           } else {
             uniqueTypes.push(transformSchemaObject({ ...schemaObject, type: t } as SchemaObject, options));
           }
diff --git a/packages/openapi-typescript/test/transform/schema-object/string.test.ts b/packages/openapi-typescript/test/transform/schema-object/string.test.ts
index e5e9a5ac1..54033d404 100644
--- a/packages/openapi-typescript/test/transform/schema-object/string.test.ts
+++ b/packages/openapi-typescript/test/transform/schema-object/string.test.ts
@@ -102,21 +102,21 @@ describe("transformSchemaObject > string", () => {
       "default + nullable",
       {
         given: { type: ["string", "null"], default: "en" },
-        want: "string",
+        want: "string | null",
       },
     ],
     [
       "default + nullable + enum",
       {
         given: { type: ["string", "null"], enum: ["en", "es", "fr", "de"], default: "en" },
-        want: '"en" | "es" | "fr" | "de"',
+        want: '"en" | "es" | "fr" | "de" | null',
       },
     ],
     [
       "default + nullable (deprecated syntax)",
       {
         given: { type: "string", default: "en", nullable: true },
-        want: "string",
+        want: "string | null",
       },
     ],
   ];