diff --git a/.chronus/changes/openapi3-fix-stray-items-array-encode-2026-6-8-0-0-1.md b/.chronus/changes/openapi3-fix-stray-items-array-encode-2026-6-8-0-0-1.md
new file mode 100644
index 00000000000..72768760867
--- /dev/null
+++ b/.chronus/changes/openapi3-fix-stray-items-array-encode-2026-6-8-0-0-1.md
@@ -0,0 +1,7 @@
+---
+changeKind: fix
+packages:
+  - "@typespec/openapi3"
+---
+
+Fix stray `items` being emitted on a property whose array type is encoded to a scalar via `@encode` (e.g. `ArrayEncoding.commaDelimited`).
diff --git a/packages/openapi3/src/encoding.ts b/packages/openapi3/src/encoding.ts
index a7e9de5832d..4ad68983afc 100644
--- a/packages/openapi3/src/encoding.ts
+++ b/packages/openapi3/src/encoding.ts
@@ -33,6 +33,10 @@ export function applyEncoding(
     }
     const newType = getSchemaForStdScalars(encodeData.type as any, options);
     targetObject.type = newType.type;
+    if (newType.type !== "array") {
+      delete targetObject.items;
+      delete targetObject.prefixItems;
+    }
     // If the target already has a format it takes priority. (e.g. int32)
     targetObject[encodedFieldName] = mergeFormatAndEncoding(
       targetObject[encodedFieldName],
diff --git a/packages/openapi3/test/array.test.ts b/packages/openapi3/test/array.test.ts
index 6e33222a247..d3e9aec0447 100644
--- a/packages/openapi3/test/array.test.ts
+++ b/packages/openapi3/test/array.test.ts
@@ -1,5 +1,6 @@
 import { deepStrictEqual, ok, strictEqual } from "assert";
-import { it } from "vitest";
+import { expect, it } from "vitest";
+import { openApiFor } from "./test-host.js";
 import { supportedVersions, worksFor } from "./works-for.js";
 
 worksFor(supportedVersions, ({ oapiForModel, openApiFor }) => {
@@ -403,3 +404,23 @@ worksFor(["3.1.0"], ({ oapiForModel }) => {
     });
   });
 });
+
+it("removes array items when an array property is encoded to a scalar", async () => {
+  const res = await openApiFor(
+    `
+    model Bar {
+      @encode(ArrayEncoding.commaDelimited)
+      prop: string[];
+    }
+
+    op getBar(): Bar;
+    `,
+    { "openapi-versions": ["3.1.0"] },
+  );
+
+  const schema = res.components.schemas.Bar.properties.prop;
+  expect(schema.type).toBe("string");
+  expect(schema.format).toBe("ArrayEncoding.commaDelimited");
+  expect(schema.items).toBeUndefined();
+  expect(schema.prefixItems).toBeUndefined();
+});