diff --git a/package-lock.json b/package-lock.json
index 25ea411..bf996f3 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -11,7 +11,7 @@
       "dependencies": {
         "@modelcontextprotocol/sdk": "^1.0.4",
         "node-fetch": "^3.3.2",
-        "zod": "^3.24.1"
+        "zod": "^4.3.6"
       },
       "bin": {
         "timetree-mcp": "dist/index.js"
@@ -2660,9 +2660,9 @@
       "license": "ISC"
     },
     "node_modules/zod": {
-      "version": "3.25.76",
-      "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
-      "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
+      "version": "4.3.6",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-4.3.6.tgz",
+      "integrity": "sha512-rftlrkhHZOcjDwkGlnUtZZkvaPHCsDATp4pGpuOOMDaTdDDXF91wuVDJoWoPsKX/3YPQ5fHuF3STjcYyKr+Qhg==",
       "license": "MIT",
       "funding": {
         "url": "https://github.com/sponsors/colinhacks"
diff --git a/package.json b/package.json
index ecf6fa5..ab325d8 100644
--- a/package.json
+++ b/package.json
@@ -24,7 +24,7 @@
   "dependencies": {
     "@modelcontextprotocol/sdk": "^1.0.4",
     "node-fetch": "^3.3.2",
-    "zod": "^3.24.1"
+    "zod": "^4.3.6"
   },
   "devDependencies": {
     "@types/node": "^22.10.5",