diff --git a/docs/plans/state.json b/docs/plans/state.json
index d52c23f..6b9dd73 100644
--- a/docs/plans/state.json
+++ b/docs/plans/state.json
@@ -43,6 +43,18 @@
       "test_status": "pnpm test:run + pnpm typecheck passing"
     },
 
+    "deployment-port-env-override": {
+      "status": "completed",
+      "date": "2026-02-16",
+      "updated": "2026-02-16",
+      "summary": "Added PORT environment variable override support so PaaS deployments can bind the gateway to the platform-assigned port without requiring config changes.",
+      "files_modified": [
+        "src/config/loader.ts",
+        "src/config/loader.test.ts"
+      ],
+      "test_status": "pnpm test:run + pnpm typecheck passing"
+    },
+
     "openclaw-gap-roadmap": {
       "file": "2026-02-15-openclaw-gap-roadmap.md",
       "status": "planned",
@@ -2132,7 +2144,7 @@
   },
 
   "overall_progress": {
-    "total_test_count": 1692,
+    "total_test_count": 1694,
     "all_tests_passing": true,
     "p0_completion": "3/3 (100%)",
     "p1_completion": "4/4 (100%)",
diff --git a/src/config/loader.test.ts b/src/config/loader.test.ts
index f2d2b5e..0175cda 100644
--- a/src/config/loader.test.ts
+++ b/src/config/loader.test.ts
@@ -102,6 +102,68 @@ telegram:
 
     rmSync(testDir, { recursive: true });
   });
+
+  it('overrides server.port from PORT env var when set', () => {
+    mkdirSync(testDir, { recursive: true });
+    const configPath = join(testDir, 'config.yaml');
+
+    const prevPort = process.env.PORT;
+    process.env.PORT = '3777';
+
+    writeFileSync(configPath, `
+telegram:
+  bot_token: "test-token"
+  allowed_chat_ids: [123]
+server:
+  port: 18800
+models:
+  default:
+    provider: anthropic
+    model: claude-sonnet
+`);
+
+    const config = loadConfig(configPath);
+    expect(config.server.port).toBe(3777);
+
+    if (prevPort !== undefined) {
+      process.env.PORT = prevPort;
+    } else {
+      delete process.env.PORT;
+    }
+
+    rmSync(testDir, { recursive: true });
+  });
+
+  it('ignores invalid PORT env var values', () => {
+    mkdirSync(testDir, { recursive: true });
+    const configPath = join(testDir, 'config.yaml');
+
+    const prevPort = process.env.PORT;
+    process.env.PORT = 'not-a-number';
+
+    writeFileSync(configPath, `
+telegram:
+  bot_token: "test-token"
+  allowed_chat_ids: [123]
+server:
+  port: 18800
+models:
+  default:
+    provider: anthropic
+    model: claude-sonnet
+`);
+
+    const config = loadConfig(configPath);
+    expect(config.server.port).toBe(18800);
+
+    if (prevPort !== undefined) {
+      process.env.PORT = prevPort;
+    } else {
+      delete process.env.PORT;
+    }
+
+    rmSync(testDir, { recursive: true });
+  });
 });
 
 describe('loadConfig with overlay', () => {
diff --git a/src/config/loader.ts b/src/config/loader.ts
index a3e09fa..e753604 100644
--- a/src/config/loader.ts
+++ b/src/config/loader.ts
@@ -81,5 +81,18 @@ export function loadConfig(configPath: string, overlayPath?: string): Config {
   }
 
   const expandedConfig = expandEnvVarsInObject(rawConfig);
-  return configSchema.parse(expandedConfig);
+  const config = configSchema.parse(expandedConfig);
+
+  // PaaS convention: if PORT is set, bind the gateway to it.
+  // This is intentionally an override (even if config.server.port is set)
+  // to make deployments on Fly/Railway/Render/Heroku-style platforms work.
+  const envPort = process.env.PORT;
+  if (envPort && /^\d+$/.test(envPort)) {
+    const port = Number(envPort);
+    if (Number.isFinite(port) && port > 0 && port <= 65535) {
+      config.server.port = port;
+    }
+  }
+
+  return config;
 }