diff --git a/lib/cache/memory-cache-store.js b/lib/cache/memory-cache-store.js
index a7a379a11bf..37cd1929811 100644
--- a/lib/cache/memory-cache-store.js
+++ b/lib/cache/memory-cache-store.js
@@ -14,8 +14,11 @@ const { Writable } = require('node:stream')
  */
 class MemoryCacheStore {
   #maxCount = Infinity
+  #maxSize = Infinity
   #maxEntrySize = Infinity
 
+  #size = 0
+
   /**
    * @type {Map<string, Map<string, GetResult[]>>}
    */
@@ -42,6 +45,17 @@ class MemoryCacheStore {
         this.#maxCount = opts.maxCount
       }
 
+      if (opts.maxSize !== undefined) {
+        if (
+          typeof opts.maxSize !== 'number' ||
+          !Number.isInteger(opts.maxSize) ||
+          opts.maxSize < 0
+        ) {
+          throw new TypeError('MemoryCacheStore options.maxSize must be a non-negative integer')
+        }
+        this.#maxSize = opts.maxSize
+      }
+
       if (opts.maxEntrySize !== undefined) {
         if (
           typeof opts.maxEntrySize !== 'number' ||
@@ -56,7 +70,7 @@ class MemoryCacheStore {
   }
 
   get isFull () {
-    return this.#arr.length >= this.#maxCount
+    return this.#arr.length >= this.#maxCount || this.#size >= this.#maxSize
   }
 
   /**
@@ -120,7 +134,12 @@ class MemoryCacheStore {
         let value = findValue(key, values)
         if (!value) {
           value = { ...opts, body }
+
           store.#arr.push(value)
+          for (const buf of body) {
+            store.#size += buf.byteLength
+          }
+
           values.push(value)
         } else {
           Object.assign(value, opts, { body })
@@ -172,6 +191,9 @@ class MemoryCacheStore {
 
     const count = Math.max(0, this.#arr.length - this.#maxCount / 2)
     for (const value of this.#arr.splice(0, count)) {
+      for (const buf of value.body) {
+        this.#size -= buf.byteLength
+      }
       value.body = null
     }
 
diff --git a/types/cache-interceptor.d.ts b/types/cache-interceptor.d.ts
index 015c2025eba..c104a0d08cd 100644
--- a/types/cache-interceptor.d.ts
+++ b/types/cache-interceptor.d.ts
@@ -79,6 +79,11 @@ declare namespace CacheHandler {
        */
     maxCount?: number
 
+    /**
+       * @default Infinity
+       */
+    maxSize?: number
+
     /**
        * @default Infinity
        */