diff --git a/langchain_postgres/vectorstores.py b/langchain_postgres/vectorstores.py
index 4092e05..5f05aea 100644
--- a/langchain_postgres/vectorstores.py
+++ b/langchain_postgres/vectorstores.py
@@ -1262,12 +1262,11 @@ def _create_filter_clause(self, filters: Any) -> Any:
                     # Then it's a field
                     return self._handle_field_filter(key, filters[key])
 
-                # Here we handle the $and, $or, and $not operators
-                if not isinstance(value, list):
-                    raise ValueError(
-                        f"Expected a list, but got {type(value)} for value: {value}"
-                    )
                 if key.lower() == "$and":
+                    if not isinstance(value, list):
+                        raise ValueError(
+                            f"Expected a list, but got {type(value)} for value: {value}"
+                        )
                     and_ = [self._create_filter_clause(el) for el in value]
                     if len(and_) > 1:
                         return sqlalchemy.and_(*and_)
@@ -1279,6 +1278,10 @@ def _create_filter_clause(self, filters: Any) -> Any:
                             "but got an empty dictionary"
                         )
                 elif key.lower() == "$or":
+                    if not isinstance(value, list):
+                        raise ValueError(
+                            f"Expected a list, but got {type(value)} for value: {value}"
+                        )
                     or_ = [self._create_filter_clause(el) for el in value]
                     if len(or_) > 1:
                         return sqlalchemy.or_(*or_)
@@ -1290,13 +1293,25 @@ def _create_filter_clause(self, filters: Any) -> Any:
                             "but got an empty dictionary"
                         )
                 elif key.lower() == "$not":
-                    not_conditions = [
-                        self._create_filter_clause(item) for item in value
-                    ]
-                    not_ = sqlalchemy.and_(
-                        *[sqlalchemy.not_(condition) for condition in not_conditions]
-                    )
-                    return not_
+                    if isinstance(value, list):
+                        not_conditions = [
+                            self._create_filter_clause(item) for item in value
+                        ]
+                        not_ = sqlalchemy.and_(
+                            *[
+                                sqlalchemy.not_(condition)
+                                for condition in not_conditions
+                            ]
+                        )
+                        return not_
+                    elif isinstance(value, dict):
+                        not_ = self._create_filter_clause(value)
+                        return sqlalchemy.not_(not_)
+                    else:
+                        raise ValueError(
+                            f"Invalid filter condition. Expected a dictionary "
+                            f"or a list but got: {type(value)}"
+                        )
                 else:
                     raise ValueError(
                         f"Invalid filter condition. Expected $and, $or or $not "
diff --git a/tests/unit_tests/fixtures/filtering_test_cases.py b/tests/unit_tests/fixtures/filtering_test_cases.py
index a354847..181e8ba 100644
--- a/tests/unit_tests/fixtures/filtering_test_cases.py
+++ b/tests/unit_tests/fixtures/filtering_test_cases.py
@@ -81,7 +81,7 @@
 
 TYPE_2_FILTERING_TEST_CASES = [
     # These involve equality checks and other operators
-    # like $ne, $gt, $gte, $lt, $lte, $not
+    # like $ne, $gt, $gte, $lt, $lte
     (
         {"id": 1},
         [1],
@@ -165,42 +165,58 @@
         {"height": {"$lte": 5.8}},
         [2, 3],
     ),
+]
+
+TYPE_3_FILTERING_TEST_CASES = [
+    # These involve usage of AND, OR and NOT operators
+    (
+        {"$or": [{"id": 1}, {"id": 2}]},
+        [1, 2],
+    ),
+    (
+        {"$or": [{"id": 1}, {"name": "bob"}]},
+        [1, 2],
+    ),
+    (
+        {"$and": [{"id": 1}, {"id": 2}]},
+        [],
+    ),
+    (
+        {"$or": [{"id": 1}, {"id": 2}, {"id": 3}]},
+        [1, 2, 3],
+    ),
     # Test for $not operator
     (
         {"$not": {"id": 1}},
         [2, 3],
     ),
     (
-        {"$not": {"name": "adam"}},
+        {"$not": [{"id": 1}]},
         [2, 3],
     ),
     (
-        {"$not": {"is_active": True}},
-        [2],
+        {"$not": {"name": "adam"}},
+        [2, 3],
     ),
     (
-        {"$not": {"height": {"$gt": 5.0}}},
-        [3],
+        {"$not": [{"name": "adam"}]},
+        [2, 3],
     ),
-]
-
-TYPE_3_FILTERING_TEST_CASES = [
-    # These involve usage of AND and OR operators
     (
-        {"$or": [{"id": 1}, {"id": 2}]},
-        [1, 2],
+        {"$not": {"is_active": True}},
+        [2],
     ),
     (
-        {"$or": [{"id": 1}, {"name": "bob"}]},
-        [1, 2],
+        {"$not": [{"is_active": True}]},
+        [2],
     ),
     (
-        {"$and": [{"id": 1}, {"id": 2}]},
-        [],
+        {"$not": {"height": {"$gt": 5.0}}},
+        [3],
     ),
     (
-        {"$or": [{"id": 1}, {"id": 2}, {"id": 3}]},
-        [1, 2, 3],
+        {"$not": [{"height": {"$gt": 5.0}}]},
+        [3],
     ),
 ]