diff --git a/src/openapi_parser/builders/schema.py b/src/openapi_parser/builders/schema.py
index efc5dbf..fcb60ba 100644
--- a/src/openapi_parser/builders/schema.py
+++ b/src/openapi_parser/builders/schema.py
@@ -139,6 +139,7 @@ def __init__(self, strict_enum: bool = True) -> None:
     def create(self, data: dict[str, Any]) -> Schema:
         """Create a schema object from a raw dict."""
         data = merge_all_of_schemas(data)
+        not_data = data.pop("not", None)
 
         if "oneOf" in data:
             data["type"] = DataType.ONE_OF
@@ -166,7 +167,12 @@ def create(self, data: dict[str, Any]) -> Schema:
 
         logger.debug(f"Building schema [type={data_type}]")
 
-        return builder_func(data)
+        schema = builder_func(data)
+
+        if not_data is not None:
+            schema.not_schema = self.create(not_data)
+
+        return schema
 
     def _null(self, data: dict[str, Any]) -> Null:
         return Null(**extract_attrs(data, {}))
diff --git a/src/openapi_parser/specification.py b/src/openapi_parser/specification.py
index f277dc1..892a6cb 100644
--- a/src/openapi_parser/specification.py
+++ b/src/openapi_parser/specification.py
@@ -94,13 +94,9 @@ class Schema:
     read_only: bool | None = field(default=False)
     write_only: bool | None = field(default=False)
     deprecated: bool | None = field(default=False)
+    not_schema: Schema | None = None
     extensions: dict[str, Any] | None = field(default_factory=dict)
 
-    # all_of: Any  # TODO
-    # one_of: Any  # TODO
-    # any_of: Any  # TODO
-    # not: Any  # TODO
-
 
 @dataclass
 class Integer(Schema):
diff --git a/tests/builders/test_not.py b/tests/builders/test_not.py
new file mode 100644
index 0000000..0abf158
--- /dev/null
+++ b/tests/builders/test_not.py
@@ -0,0 +1,75 @@
+from typing import Any
+
+import pytest
+
+from openapi_parser.builders.schema import SchemaFactory
+from openapi_parser.enumeration import DataType
+from openapi_parser.specification import (
+    AnyOf,
+    Array,
+    Boolean,
+    Integer,
+    Number,
+    Object,
+    Property,
+    Schema,
+    String,
+)
+
+data_provider = (
+    (
+        {
+            "type": "string",
+            "not": {"type": "integer"},
+        },
+        String(
+            type=DataType.STRING,
+            not_schema=Integer(type=DataType.INTEGER),
+        ),
+    ),
+    (
+        {
+            "type": "object",
+            "properties": {
+                "name": {"type": "string"},
+            },
+            "not": {"type": "integer"},
+        },
+        Object(
+            type=DataType.OBJECT,
+            properties=[
+                Property(name="name", schema=String(type=DataType.STRING)),
+            ],
+            not_schema=Integer(type=DataType.INTEGER),
+        ),
+    ),
+    (
+        {
+            "not": {"type": "integer"},
+        },
+        AnyOf(
+            type=DataType.ANY_OF,
+            schemas=[
+                Integer(type=DataType.INTEGER),
+                Number(type=DataType.NUMBER),
+                String(type=DataType.STRING),
+                Boolean(type=DataType.BOOLEAN),
+                Array(type=DataType.ARRAY),
+                Object(type=DataType.OBJECT),
+            ],
+            not_schema=Integer(type=DataType.INTEGER),
+        ),
+    ),
+    (
+        {
+            "type": "string",
+        },
+        String(type=DataType.STRING),
+    ),
+)
+
+
+@pytest.mark.parametrize(["data", "expected"], data_provider)
+def test_not_builder(data: dict[str, Any], expected: Schema) -> None:
+    factory = SchemaFactory()
+    assert expected == factory.create(data)
diff --git a/tests/data/swagger.yml b/tests/data/swagger.yml
index c72775f..8e711c0 100644
--- a/tests/data/swagger.yml
+++ b/tests/data/swagger.yml
@@ -120,6 +120,8 @@ components:
       allowReserved: true
       schema:
         type: integer
+        not:
+          type: string
 
     Offset:
       name: offset
diff --git a/tests/openapi_fixture.py b/tests/openapi_fixture.py
index 961f1ad..ae0b03e 100644
--- a/tests/openapi_fixture.py
+++ b/tests/openapi_fixture.py
@@ -341,7 +341,10 @@ def create_specification() -> Specification:
                             style=QueryParameterStyle.FORM,
                             allow_reserved=True,
                             example=10,
-                            schema=Integer(type=DataType.INTEGER),
+                            schema=Integer(
+                                type=DataType.INTEGER,
+                                not_schema=String(type=DataType.STRING),
+                            ),
                         ),
                         Parameter(
                             name="offset",