diff --git a/packages/happy-dom/src/cookie/urilities/CookieStringUtility.ts b/packages/happy-dom/src/cookie/urilities/CookieStringUtility.ts
index afb94052..11409bfc 100644
--- a/packages/happy-dom/src/cookie/urilities/CookieStringUtility.ts
+++ b/packages/happy-dom/src/cookie/urilities/CookieStringUtility.ts
@@ -15,12 +15,15 @@ export default class CookieStringUtility {
 	 */
 	public static stringToCookie(originURL: URL, cookieString: string): ICookie | null {
 		const parts = cookieString.split(';');
-		const [key, ...value] = parts.shift().split('=');
+		const part = parts.shift();
+		const index = part.indexOf('=');
+		const key = index !== -1 ? part.slice(0, index).trim() : part.trim();
+		const value = index !== -1 ? part.slice(index + 1).trim() : null;
 
 		const cookie: ICookie = {
 			// Required
-			key: key.trim(),
-			value: value.length ? value.join('=') : null,
+			key,
+			value,
 			originURL,
 
 			// Optional
@@ -38,9 +41,10 @@ export default class CookieStringUtility {
 		}
 
 		for (const part of parts) {
-			const [_key, ..._value] = part.split('=');
-			const key = _key.trim().toLowerCase();
-			const value = _value.join('=').trim();
+			const index = part.indexOf('=');
+			const key =
+				index !== -1 ? part.slice(0, index).trim().toLowerCase() : part.trim().toLowerCase();
+			const value = index !== -1 ? part.slice(index + 1).trim() : '';
 
 			switch (key) {
 				case 'expires':
diff --git a/packages/happy-dom/test/cookie/CookieContainer.test.ts b/packages/happy-dom/test/cookie/CookieContainer.test.ts
index 192a2981..bc65437c 100644
--- a/packages/happy-dom/test/cookie/CookieContainer.test.ts
+++ b/packages/happy-dom/test/cookie/CookieContainer.test.ts
@@ -29,7 +29,9 @@ describe('CookieContainer', () => {
 						`key1=value1; Expires=${new Date(expires).toString()};`
 					)
 				),
-				<ICookie>CookieStringUtility.stringToCookie(originURL, `key2=value2; Max-Age=${maxAge};`),
+				<ICookie>(
+					CookieStringUtility.stringToCookie(originURL, `key2   =    value2   ; Max-Age=${maxAge};`)
+				),
 				<ICookie>CookieStringUtility.stringToCookie(originURL, `key3=value3; Domain=example.com;`),
 				<ICookie>CookieStringUtility.stringToCookie(originURL, `key4=value4; Domain=other.com;`),
 				<ICookie>(