diff --git a/packages/next/server/config-schema.ts b/packages/next/server/config-schema.ts
index f9d18748f444..841a57da63fa 100644
--- a/packages/next/server/config-schema.ts
+++ b/packages/next/server/config-schema.ts
@@ -333,7 +333,14 @@ const configSchema = {
           type: 'boolean',
         },
         optimizeCss: {
-          type: 'boolean',
+          oneOf: [
+            {
+              type: 'boolean',
+            },
+            {
+              type: 'object',
+            },
+          ] as any,
         },
         outputFileTracingRoot: {
           minLength: 1,
diff --git a/packages/next/server/config-shared.ts b/packages/next/server/config-shared.ts
index a1dbbb5110e0..ff38d8e304ca 100644
--- a/packages/next/server/config-shared.ts
+++ b/packages/next/server/config-shared.ts
@@ -94,7 +94,10 @@ export interface ExperimentalConfig {
   isrFlushToDisk?: boolean
   workerThreads?: boolean
   pageEnv?: boolean
-  optimizeCss?: boolean
+  // optimizeCss can be boolean or critters' option object
+  // Use Record<string, unknown> as critters doesn't export its Option type
+  // https://github.com/GoogleChromeLabs/critters/blob/a590c05f9197b656d2aeaae9369df2483c26b072/packages/critters/src/index.d.ts
+  optimizeCss?: boolean | Record<string, unknown>
   nextScriptWorkers?: boolean
   scrollRestoration?: boolean
   externalDir?: boolean