diff --git a/tools/isledecomp/isledecomp/cvdump/types.py b/tools/isledecomp/isledecomp/cvdump/types.py
index 381c27e9..b39ea248 100644
--- a/tools/isledecomp/isledecomp/cvdump/types.py
+++ b/tools/isledecomp/isledecomp/cvdump/types.py
@@ -221,7 +221,7 @@ class CvdumpTypesParser:
     )
     LF_ENUM_UDT = re.compile(r"^\s*UDT\((?P<udt>0x\w+)\)$")
     LF_UNION_LINE = re.compile(
-        r"^.*field list type (?P<field_type>0x\w+),.*Size = (?P<size>\d+)\s*,class name = (?P<name>(?:[^,]|,\S)+),\s.*UDT\((?P<udt>0x\w+)\)$"
+        r"^.*field list type (?P<field_type>0x\w+),.*Size = (?P<size>\d+)\s*,class name = (?P<name>(?:[^,]|,\S)+)(?:,\s.*UDT\((?P<udt>0x\w+)\))?$"
     )
 
     MODES_OF_INTEREST = {
@@ -659,4 +659,5 @@ def read_union_line(self, line: str):
             self._set("is_forward_ref", True)
 
         self._set("size", int(match.group("size")))
-        self._set("udt", normalize_type_id(match.group("udt")))
+        if match.group("udt") is not None:
+            self._set("udt", normalize_type_id(match.group("udt")))
diff --git a/tools/isledecomp/tests/test_cvdump_types.py b/tools/isledecomp/tests/test_cvdump_types.py
index e271040c..324870eb 100644
--- a/tools/isledecomp/tests/test_cvdump_types.py
+++ b/tools/isledecomp/tests/test_cvdump_types.py
@@ -551,3 +551,26 @@ def test_fieldlist_enumerate(parser: CvdumpTypesParser):
             {"name": "c_text", "value": 4},
         ],
     }
+
+
+UNNAMED_UNION_DATA = """
+0x369d : Length = 34, Leaf = 0x1203 LF_FIELDLIST
+    list[0] = LF_MEMBER, public, type = T_32PRCHAR(0470), offset = 0
+        member name = 'sz'
+    list[1] = LF_MEMBER, public, type = T_32PUSHORT(0421), offset = 0
+        member name = 'wz'
+
+0x369e : Length = 22, Leaf = 0x1506 LF_UNION
+    # members = 2,  field list type 0x369d, NESTED, Size = 4    ,class name = __unnamed
+"""
+
+
+def test_unnamed_union():
+    """Make sure we can parse anonymous union types without a UDT"""
+    parser = CvdumpTypesParser()
+    for line in UNNAMED_UNION_DATA.split("\n"):
+        parser.read_line(line)
+
+    # Make sure we can parse the members line
+    union = parser.keys["0x369e"]
+    assert union["size"] == 4