diff --git a/sphinx/ext/napoleon/docstring.py b/sphinx/ext/napoleon/docstring.py
index 36c713170..19eeeb6c6 100644
--- a/sphinx/ext/napoleon/docstring.py
+++ b/sphinx/ext/napoleon/docstring.py
@@ -37,7 +37,7 @@ _xref_or_code_regex = re.compile(
     r'((?::(?:[a-zA-Z0-9]+[\-_+:.])*[a-zA-Z0-9]+:`.+?`)|'
     r'(?:``.+``))')
 _xref_regex = re.compile(
-    r'(?::(?:[a-zA-Z0-9]+[\-_+:.])*[a-zA-Z0-9]+:`.+?`)'
+    r'(?:(?::(?:[a-zA-Z0-9]+[\-_+:.])*[a-zA-Z0-9]+:)?`.+?`)'
 )
 _bullet_list_regex = re.compile(r'^(\*|\+|\-)(\s+\S|\s*$)')
 _enumerated_list_regex = re.compile(