diff --git a/packages/message-parser/src/grammar.pegjs b/packages/message-parser/src/grammar.pegjs
index 7c636b6089..e76ebe0c72 100644
--- a/packages/message-parser/src/grammar.pegjs
+++ b/packages/message-parser/src/grammar.pegjs
@@ -177,15 +177,20 @@ anyText
   / [\x61-\x7A] // a b c d e f g h i j k l m n o p q r s t u v w x y z
   / nonascii
 
-utf8_names_validation = $[0-9a-zA-Z-_.]+
+utf8_names_validation = $([-_.] / alphaChar / decimalNumberChar)+
 
-matrix_server_validation = ":" utf8_names_validation
+username_matrix_server_validation = ":" utf8_names_validation
+
+username_email_validation = "@" utf8_names_validation
 
 UserMention
   = t:Text "@"+ user:utf8_names_validation {
       return reducePlainTexts([t, plain('@' + user)])[0];
     }
-  / "@"+ user:$(utf8_names_validation matrix_server_validation) {
+  / "@"+ user:$(utf8_names_validation username_matrix_server_validation) {
+      return mentionUser(user);
+    }
+  / "@"+ user:$(utf8_names_validation username_email_validation) {
       return mentionUser(user);
     }
   / "@"+ user:utf8_names_validation { return mentionUser(user); }
diff --git a/packages/message-parser/tests/mention.test.ts b/packages/message-parser/tests/mention.test.ts
index a193393048..5a86d5587a 100644
--- a/packages/message-parser/tests/mention.test.ts
+++ b/packages/message-parser/tests/mention.test.ts
@@ -13,6 +13,22 @@ test.each([
     '@marcos.defendi:matrix.org',
     [paragraph([mentionUser('marcos.defendi:matrix.org')])],
   ],
+  ['@username@example.com', [paragraph([mentionUser('username@example.com')])]],
+  [
+    '@099fnd2ee@example.com',
+    [paragraph([mentionUser('099fnd2ee@example.com')])],
+  ],
+  ['@téstãçâò', [paragraph([mentionUser('téstãçâò')])]],
+  ['@สมชาย', [paragraph([mentionUser('สมชาย')])]],
+  ['@李祖阳', [paragraph([mentionUser('李祖阳')])]],
+  ['@あおい', [paragraph([mentionUser('あおい')])]],
+  ['@アオイ', [paragraph([mentionUser('アオイ')])]],
+  ['@Владимир', [paragraph([mentionUser('Владимир')])]],
+  ['@Кириллица', [paragraph([mentionUser('Кириллица')])]],
+  [
+    'test @Кириллица test',
+    [paragraph([plain('test '), mentionUser('Кириллица'), plain(' test')])],
+  ],
 ])('parses %p', (input, output) => {
   expect(parse(input)).toMatchObject(output);
 });