diff --git a/.changeset/silver-toys-roll.md b/.changeset/silver-toys-roll.md
new file mode 100644
index 0000000000..190623c482
--- /dev/null
+++ b/.changeset/silver-toys-roll.md
@@ -0,0 +1,6 @@
+---
+"@latticexyz/store": patch
+"@latticexyz/world": patch
+---
+
+`defineStore` and `defineWorld` will now throw a type error if an unexpected config option is used.
diff --git a/packages/store/ts/config/v2/store.test.ts b/packages/store/ts/config/v2/store.test.ts
index 458f356d6a..0faf3c999e 100644
--- a/packages/store/ts/config/v2/store.test.ts
+++ b/packages/store/ts/config/v2/store.test.ts
@@ -516,4 +516,13 @@ describe("defineStore", () => {
 
     defineStore(config);
   });
+
+  it("should throw if config has unexpected key", () => {
+    attest(() =>
+      defineStore({
+        // @ts-expect-error Invalid config option
+        invalidOption: "nope",
+      }),
+    ).type.errors("`invalidOption` is not a valid Store config option.");
+  });
 });
diff --git a/packages/store/ts/config/v2/store.ts b/packages/store/ts/config/v2/store.ts
index 2305f2fba4..0922998f56 100644
--- a/packages/store/ts/config/v2/store.ts
+++ b/packages/store/ts/config/v2/store.ts
@@ -1,4 +1,4 @@
-import { flatMorph, narrow } from "@arktype/util";
+import { ErrorMessage, flatMorph, narrow } from "@arktype/util";
 import { get, hasOwnKey, mergeIfUndefined } from "./generics";
 import { UserTypes } from "./output";
 import { CONFIG_DEFAULTS } from "./defaults";
@@ -23,7 +23,7 @@ export type validateStore<store> = {
         ? narrow<store[key]>
         : key extends keyof StoreInput
           ? StoreInput[key]
-          : never;
+          : ErrorMessage<`\`${key & string}\` is not a valid Store config option.`>;
 };
 
 export function validateStore(store: unknown): asserts store is StoreInput {
diff --git a/packages/world/ts/config/v2/world.test.ts b/packages/world/ts/config/v2/world.test.ts
index 94ab0f6842..245e9c9e26 100644
--- a/packages/world/ts/config/v2/world.test.ts
+++ b/packages/world/ts/config/v2/world.test.ts
@@ -752,4 +752,13 @@ describe("defineWorld", () => {
 
     defineWorld(config);
   });
+
+  it("should throw if config has unexpected key", () => {
+    attest(() =>
+      defineWorld({
+        // @ts-expect-error Invalid config option
+        invalidOption: "nope",
+      }),
+    ).type.errors("`invalidOption` is not a valid World config option.");
+  });
 });
diff --git a/packages/world/ts/config/v2/world.ts b/packages/world/ts/config/v2/world.ts
index 13898d5542..b26b358677 100644
--- a/packages/world/ts/config/v2/world.ts
+++ b/packages/world/ts/config/v2/world.ts
@@ -33,7 +33,7 @@ export type validateWorld<world> = {
             ErrorMessage<`Namespaces config will be enabled soon.`>
           : key extends keyof WorldInput
             ? conform<world[key], WorldInput[key]>
-            : world[key];
+            : ErrorMessage<`\`${key & string}\` is not a valid World config option.`>;
 };
 
 export function validateWorld(world: unknown): asserts world is WorldInput {