diff --git a/.chronus/changes/termsOfServiceUrlCheck-2024-8-23-12-59-15.md b/.chronus/changes/termsOfServiceUrlCheck-2024-8-23-12-59-15.md
new file mode 100644
index 0000000000..541f10403d
--- /dev/null
+++ b/.chronus/changes/termsOfServiceUrlCheck-2024-8-23-12-59-15.md
@@ -0,0 +1,7 @@
+---
+changeKind: fix
+packages:
+  - "@typespec/openapi"
+---
+
+`@info` decorator validate `termsOfService` is a valid url
\ No newline at end of file
diff --git a/packages/openapi/src/decorators.ts b/packages/openapi/src/decorators.ts
index d8d41ac379..bf2dae3acf 100644
--- a/packages/openapi/src/decorators.ts
+++ b/packages/openapi/src/decorators.ts
@@ -185,6 +185,11 @@ export const $info: InfoDecorator = (
   if (data === undefined) {
     return;
   }
+  if (data.termsOfService) {
+    if (!validateIsUri(context, data.termsOfService, "TermsOfService")) {
+      return;
+    }
+  }
   setInfo(context.program, entity, data);
 };
 
@@ -214,3 +219,17 @@ export function resolveInfo(program: Program, entity: Namespace): AdditionalInfo
 function omitUndefined<T extends Record<string, unknown>>(data: T): T {
   return Object.fromEntries(Object.entries(data).filter(([k, v]) => v !== undefined)) as any;
 }
+
+function validateIsUri(context: DecoratorContext, url: string, propertyName: string) {
+  try {
+    new URL(url);
+    return true;
+  } catch {
+    reportDiagnostic(context.program, {
+      code: "not-url",
+      target: context.getArgumentTarget(0)!,
+      format: { property: propertyName, value: url },
+    });
+    return false;
+  }
+}
diff --git a/packages/openapi/src/lib.ts b/packages/openapi/src/lib.ts
index 0c5c097fba..7201672536 100644
--- a/packages/openapi/src/lib.ts
+++ b/packages/openapi/src/lib.ts
@@ -16,6 +16,12 @@ export const $lib = createTypeSpecLibrary({
         parameter: paramMessage`Duplicate parameter key: '${"value"}'. Check @friendlyName decorators and overlap with types in TypeSpec or service namespace.`,
       },
     },
+    "not-url": {
+      severity: "error",
+      messages: {
+        default: paramMessage`${"property"}: ${"value"} is not a valid URL.`,
+      },
+    },
   },
 });
 
diff --git a/packages/openapi/test/decorators.test.ts b/packages/openapi/test/decorators.test.ts
index dbc2b394a3..87cf1d6b52 100644
--- a/packages/openapi/test/decorators.test.ts
+++ b/packages/openapi/test/decorators.test.ts
@@ -152,6 +152,18 @@ describe("openapi: decorators", () => {
   });
 
   describe("@info", () => {
+    it("emit diagnostic if termsOfService is not a valid url", async () => {
+      const diagnostics = await runner.diagnose(`
+        @info({termsOfService:"notvalidurl"})
+        @test namespace Service {}
+      `);
+
+      expectDiagnostics(diagnostics, {
+        code: "@typespec/openapi/not-url",
+        message: "TermsOfService: notvalidurl is not a valid URL.",
+      });
+    });
+
     it("emit diagnostic if use on non namespace", async () => {
       const diagnostics = await runner.diagnose(`
         @info({})