diff --git a/releasenotes/notes/lex-namespace-annotations-34e856acd9837226.yaml b/releasenotes/notes/lex-namespace-annotations-34e856acd9837226.yaml
new file mode 100644
index 0000000..ef242ef
--- /dev/null
+++ b/releasenotes/notes/lex-namespace-annotations-34e856acd9837226.yaml
@@ -0,0 +1,4 @@
+---
+fixes:
+  - |
+    Annotation keywords will now be correctly lexed as a single ``Token.Name.Decorator`` token.
diff --git a/src/openqasm_pygments/qasm3.py b/src/openqasm_pygments/qasm3.py
index 5597d77..5469885 100644
--- a/src/openqasm_pygments/qasm3.py
+++ b/src/openqasm_pygments/qasm3.py
@@ -75,7 +75,7 @@ def _defcalgrammar_callback(self, match):
     tokens = {
         "root": [
             (r"^[ \t]*#?pragma", token.Comment.Preproc, "pragma"),
-            (r"^[ \t]*@\w+", token.Name.Decorator, "annotation"),
+            (r"^[ \t]*@\w+(\.\w+)*", token.Name.Decorator, "annotation"),
             (r"[ \r\n\t]+", token.Whitespace),
             (r"\bOPENQASM\b", token.Comment.Preproc, "version"),
             (r"//.*$", token.Comment.Single),
diff --git a/tests/test_qasm3_lexer.py b/tests/test_qasm3_lexer.py
index 07ddec6..a00d48e 100644
--- a/tests/test_qasm3_lexer.py
+++ b/tests/test_qasm3_lexer.py
@@ -68,6 +68,23 @@ def test_for_loop_variable_not_callable(lexer_qasm3):
     ]
 
 
+def test_annotation_namespace(lexer_qasm3):
+    text = """\
+@annotation
+@namespace.annotation
+@namespace1.namespace2.annotation
+qubit q;
+"""
+    assert _remove_whitespace(lexer_qasm3.get_tokens(text)) == [
+        (token.Name.Decorator, "@annotation"),
+        (token.Name.Decorator, "@namespace.annotation"),
+        (token.Name.Decorator, "@namespace1.namespace2.annotation"),
+        (token.Keyword.Type, "qubit"),
+        (token.Name, "q"),
+        (token.Punctuation, ";"),
+    ]
+
+
 class TestPulseLexerDelegation:
     def test_inferred_known_alias(self, lexer_qasm3):
         # This uses a very (!) non-standard pulse-grammar lexer to test delegation