diff --git a/doc/grammars/lexemes.pp3 b/doc/grammars/lexemes.pp3
index 7859a714..d69176ff 100644
--- a/doc/grammars/lexemes.pp3
+++ b/doc/grammars/lexemes.pp3
@@ -173,8 +173,8 @@
  * so that the "@baz" of "@author Foo <foo@baz.com>" belongs to the description
  * it is written in.
  */
-%token T_PHPDOC_TAG_WS               (?<=[\x09\x20])@(?:[a-z][a-z0-9-\\]+:)?[a-z][a-z0-9-\\]*+
-%token T_PHPDOC_TAG                  @(?:[a-z][a-z0-9-\\]+:)?[a-z][a-z0-9-\\]*+
+%token T_PHPDOC_TAG_WS               (?<=[\x09\x20])@(?:[a-z][a-z0-9-\\]+:)?[a-z][a-z0-9_\\-]*+
+%token T_PHPDOC_TAG                  @(?:[a-z][a-z0-9-\\]+:)?[a-z][a-z0-9_\\-]*+
 %token T_DOCTRINE_TAG_WS             (?<=[\x09\x20])@[a-z_\\][a-z0-9_:\\]*[a-z_][a-z0-9_]*
 %token T_DOCTRINE_TAG                @[a-z_\\][a-z0-9_:\\]*[a-z_][a-z0-9_]*
 %token T_PHPDOC_EOL                  \r?+\n[\x09\x20]*+(?:\*(?!/)\x20?+)?
diff --git a/src/Lexer/Lexer.php b/src/Lexer/Lexer.php
index c470100c..01de5857 100644
--- a/src/Lexer/Lexer.php
+++ b/src/Lexer/Lexer.php
@@ -182,7 +182,7 @@ private function generateRegexp(): string
 
 			self::TOKEN_OPEN_PHPDOC => '/\\*\\*(?=\\s)\\x20?+',
 			self::TOKEN_CLOSE_PHPDOC => '\\*/',
-			self::TOKEN_PHPDOC_TAG => '@(?:[a-z][a-z0-9-\\\\]+:)?[a-z][a-z0-9-\\\\]*+',
+			self::TOKEN_PHPDOC_TAG => '@(?:[a-z][a-z0-9-\\\\]+:)?[a-z][a-z0-9_\\\\-]*+',
 			self::TOKEN_DOCTRINE_TAG => '@[a-z_\\\\][a-z0-9_\:\\\\]*[a-z_][a-z0-9_]*',
 			self::TOKEN_PHPDOC_EOL => '\\r?+\\n[\\x09\\x20]*+(?:\\*(?!/)\\x20?+)?',
 
diff --git a/tests/PHPStan/Parser/PhpDocParserTest.php b/tests/PHPStan/Parser/PhpDocParserTest.php
index eacece63..238d4a38 100644
--- a/tests/PHPStan/Parser/PhpDocParserTest.php
+++ b/tests/PHPStan/Parser/PhpDocParserTest.php
@@ -6338,6 +6338,30 @@ public function provideTagsWithNumbers(): Iterator
 
 	public function provideTagsWithBackslash(): Iterator
 	{
+		yield [
+			'OK tag with underscore in it',
+			'/** @Foo_Bar User */',
+			new PhpDocNode([
+				new PhpDocTagNode(
+					'@Foo_Bar',
+					new GenericTagValueNode('User'),
+				),
+			]),
+		];
+
+		yield [
+			'OK tag with underscore in it and parenthesis',
+			'/** @Foo\Bar_Baz(name="column_id") */',
+			new PhpDocNode([
+				new PhpDocTagNode(
+					'@Foo\Bar_Baz',
+					new DoctrineTagValueNode(new DoctrineAnnotation('@Foo\Bar_Baz', [
+						new DoctrineArgument(new IdentifierTypeNode('name'), new DoctrineConstExprStringNode('column_id')),
+					]), ''),
+				),
+			]),
+		];
+
 		yield [
 			'OK without description and tag with backslashes in it',
 			'/** @ORM\Mapping\Entity User */',