diff --git a/tagstudio/src/core/library/alchemy/visitors.py b/tagstudio/src/core/library/alchemy/visitors.py
index 2b649b41..1e9ec043 100644
--- a/tagstudio/src/core/library/alchemy/visitors.py
+++ b/tagstudio/src/core/library/alchemy/visitors.py
@@ -37,6 +37,11 @@ class SQLBoolExpressionBuilder(BaseVisitor):
             return Entry.suffix.in_(map(lambda x: x.replace(".", ""), extensions))
         elif node.type == ConstraintType.FileType:
             return Entry.suffix.ilike(node.value)
+        elif node.type == ConstraintType.Special:  # noqa: SIM102 unnecessary once there is a second special constraint
+            if node.value.lower() == "untagged":
+                return ~Entry.id.in_(
+                    select(Entry.id).join(Entry.tag_box_fields).join(TagBoxField.tags)
+                )
 
         # raise exception if Constraint stays unhandled
         raise NotImplementedError("This type of constraint is not implemented yet")
diff --git a/tagstudio/src/core/query_lang/ast.py b/tagstudio/src/core/query_lang/ast.py
index 820a79c5..d4346964 100644
--- a/tagstudio/src/core/query_lang/ast.py
+++ b/tagstudio/src/core/query_lang/ast.py
@@ -9,6 +9,7 @@ class ConstraintType(Enum):  # TODO add remaining ones
     MediaType = 2
     FileType = 3
     Path = 4
+    Special = 5
 
     @staticmethod
     def from_string(text: str) -> "ConstraintType":
@@ -18,6 +19,7 @@ class ConstraintType(Enum):  # TODO add remaining ones
             "mediatype": ConstraintType.MediaType,
             "filetype": ConstraintType.FileType,
             "path": ConstraintType.Path,
+            "special": ConstraintType.Special,
         }.get(text.lower(), None)