diff --git a/polygraph/types/type_builder.py b/polygraph/types/type_builder.py
index 2b20577..fcce7f3 100644
--- a/polygraph/types/type_builder.py
+++ b/polygraph/types/type_builder.py
@@ -2,7 +2,11 @@ from functools import wraps
 
 from polygraph.exceptions import PolygraphSchemaError, PolygraphValueError
 from polygraph.types.api import typedef
-from polygraph.types.basic_type import PolygraphOutputType, PolygraphType
+from polygraph.types.basic_type import (
+    PolygraphOutputType,
+    PolygraphType,
+    PolygraphTypeMeta,
+)
 from polygraph.types.definitions import TypeKind
 from polygraph.utils.deduplicate import deduplicate
 
@@ -39,7 +43,15 @@ def type_builder_cache(method):
     return wrapper
 
 
-class Union(PolygraphOutputType, PolygraphType):
+class TypeBuilderMeta(PolygraphTypeMeta):
+    def __getitem__(self, value):
+        try:
+            return self.__new__(self, *value)
+        except TypeError:
+            return self.__new__(self, value)
+
+
+class Union(PolygraphOutputType, PolygraphType, metaclass=TypeBuilderMeta):
     """
     GraphQL Unions represent an object that could be one of a list of
     GraphQL Object types, but provides for no guaranteed fields between
@@ -77,7 +89,7 @@ class Union(PolygraphOutputType, PolygraphType):
         return type(name, bases, attrs)
 
 
-class List(PolygraphOutputType, PolygraphType):
+class List(PolygraphOutputType, PolygraphType, metaclass=TypeBuilderMeta):
     """
     A GraphQL list is a special collection type which declares the
     type of each item in the List (referred to as the item type of
@@ -109,7 +121,7 @@ class List(PolygraphOutputType, PolygraphType):
         return type(name, bases, attrs)
 
 
-class NonNull(PolygraphType):
+class NonNull(PolygraphType, metaclass=TypeBuilderMeta):
     """
     Represents a type for which null is not a valid result.
     """

Use square brackets for wrapping types, e.g. `Union[X, Y]`
diff --git a/polygraph/types/tests/helper.py b/polygraph/types/tests/helper.py
new file mode 100644
index 0000000..59d17f2
--- /dev/null
+++ b/polygraph/types/tests/helper.py
@@ -0,0 +1,23 @@
+from polygraph.types.decorators import field
+from polygraph.types.object_type import ObjectType
+from polygraph.types.scalar import Int, String
+
+
+class Person(ObjectType):
+    @field()
+    def name(self) -> String:
+        pass
+
+    @field()
+    def age(self) -> Int:
+        pass
+
+
+class Animal(ObjectType):
+    @field()
+    def name(self) -> String:
+        pass
+
+    @field()
+    def sound(self) -> String:
+        pass
diff --git a/polygraph/types/tests/test_types.py b/polygraph/types/tests/test_types.py
index d08d30f..cb6bf0a 100644
--- a/polygraph/types/tests/test_types.py
+++ b/polygraph/types/tests/test_types.py
@@ -50,6 +50,9 @@ class NonNullTest(TestCase):
         with self.assertRaises(TypeError):
             NonNull(NonNullString)
 
+    def test_square_bracket_notation(self):
+        self.assertEqual(NonNull(String), NonNull[String])
+
 
 class ListTest(TestCase):
 
@@ -67,3 +70,6 @@ class ListTest(TestCase):
         self.assertEqual(string_list(["a", "b", "c"]), ["a", "b", "c"])
         with self.assertRaises(PolygraphValueError):
             string_list(["a", "b", "c", None])
+
+    def test_square_bracket_notation(self):
+        self.assertEqual(List(Int), List[Int])
diff --git a/polygraph/types/tests/test_union.py b/polygraph/types/tests/test_union.py
index e98ba92..1150486 100644
--- a/polygraph/types/tests/test_union.py
+++ b/polygraph/types/tests/test_union.py
@@ -1,17 +1,23 @@
-from unittest import TestCase, skip
+from unittest import TestCase
 
 from polygraph.exceptions import PolygraphValueError
 from polygraph.types.scalar import Float, Int, String
+from polygraph.types.tests.helper import Animal, Person
 from polygraph.types.type_builder import Union
 
 
 class UnionTypeTest(TestCase):
 
+    def test_square_bracket_notation(self):
+        self.assertEqual(
+            Union(Person, Animal),
+            Union[Person, Animal],
+        )
+
     def test_commutativity(self):
         self.assertEqual(Union(String, Int), Union(Int, String))
         self.assertEqual(Union(String, Int, Float), Union(Float, String, Int))
 
-    @skip
     def test_associativity(self):
         self.assertEqual(
             Union(Union(String, Int), Float),

pip install -e .[dev]
parse_log_pytest
pytest
pytest pytest-cov
3.6
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
args==0.1.0
attrs @ file:///opt/conda/conda-bld/attrs_1642510447205/work
autopep8==2.0.4
backcall==0.2.0
certifi==2021.5.30
charset-normalizer==2.0.12
clint==0.5.1
coverage==6.2
decorator==5.1.1
distlib==0.3.9
filelock==3.4.1
flake8==2.5.5
graphql-core==3.2.6
idna==3.10
importlib-metadata==4.8.3
importlib-resources==5.4.0
iniconfig @ file:///home/linux1/recipes/ci/iniconfig_1610983019677/work
ipython==7.16.3
ipython-genutils==0.2.0
isort==5.10.1
jedi==0.17.2
mccabe==0.4.0
more-itertools @ file:///tmp/build/80754af9/more-itertools_1637733554872/work
packaging @ file:///tmp/build/80754af9/packaging_1637314298585/work
parso==0.7.1
pbr==6.1.1
pep8==1.7.1
pexpect==4.9.0
pickleshare==0.7.5
pkginfo==1.10.0
platformdirs==2.4.0
pluggy @ file:///tmp/build/80754af9/pluggy_1615976315926/work
-e git+https://github.com/polygraph-python/polygraph.git@f0897942b1fb6d6412a81852646eb94697d4632f#egg=polygraph
prompt-toolkit==3.0.36
ptyprocess==0.7.0
pudb==2017.1.2
py @ file:///opt/conda/conda-bld/py_1644396412707/work
pycodestyle==2.10.0
pyflakes==1.0.0
Pygments==2.14.0
pyparsing @ file:///tmp/build/80754af9/pyparsing_1635766073266/work
pytest==6.2.4
pytest-cov==4.0.0
requests==2.27.1
requests-toolbelt==1.0.0
six==1.17.0
stevedore==3.5.2
toml @ file:///tmp/build/80754af9/toml_1616166611790/work
tomli==1.2.3
traitlets==4.3.3
twine==1.8.1
typing_extensions @ file:///opt/conda/conda-bld/typing_extensions_1647553014482/work
urllib3==1.26.20
urwid==2.1.2
virtualenv==20.17.1
virtualenv-clone==0.5.7
virtualenvwrapper==4.8.4
wcwidth==0.2.13
zipp @ file:///tmp/build/80754af9/zipp_1633618647012/work

name: polygraph
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - attrs=21.4.0=pyhd3eb1b0_0
  - ca-certificates=2025.2.25=h06a4308_0
  - certifi=2021.5.30=py36h06a4308_0
  - importlib_metadata=4.8.1=hd3eb1b0_0
  - iniconfig=1.1.1=pyhd3eb1b0_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.3=he6710b0_2
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - more-itertools=8.12.0=pyhd3eb1b0_0
  - ncurses=6.4=h6a678d5_0
  - openssl=1.1.1w=h7f8727e_0
  - packaging=21.3=pyhd3eb1b0_0
  - pip=21.2.2=py36h06a4308_0
  - pluggy=0.13.1=py36h06a4308_0
  - py=1.11.0=pyhd3eb1b0_0
  - pyparsing=3.0.4=pyhd3eb1b0_0
  - pytest=6.2.4=py36h06a4308_2
  - python=3.6.13=h12debd9_1
  - readline=8.2=h5eee18b_0
  - setuptools=58.0.4=py36h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - toml=0.10.2=pyhd3eb1b0_0
  - typing_extensions=4.1.1=pyh06a4308_0
  - wheel=0.37.1=pyhd3eb1b0_0
  - xz=5.6.4=h5eee18b_1
  - zipp=3.6.0=pyhd3eb1b0_0
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - args==0.1.0
      - autopep8==2.0.4
      - backcall==0.2.0
      - charset-normalizer==2.0.12
      - clint==0.5.1
      - coverage==6.2
      - decorator==5.1.1
      - distlib==0.3.9
      - filelock==3.4.1
      - flake8==2.5.5
      - graphql-core==3.2.6
      - idna==3.10
      - importlib-metadata==4.8.3
      - importlib-resources==5.4.0
      - ipython==7.16.3
      - ipython-genutils==0.2.0
      - isort==5.10.1
      - jedi==0.17.2
      - mccabe==0.4.0
      - parso==0.7.1
      - pbr==6.1.1
      - pep8==1.7.1
      - pexpect==4.9.0
      - pickleshare==0.7.5
      - pkginfo==1.10.0
      - platformdirs==2.4.0
      - prompt-toolkit==3.0.36
      - ptyprocess==0.7.0
      - pudb==2017.1.2
      - pycodestyle==2.10.0
      - pyflakes==1.0.0
      - pygments==2.14.0
      - pytest-cov==4.0.0
      - requests==2.27.1
      - requests-toolbelt==1.0.0
      - six==1.17.0
      - stevedore==3.5.2
      - tomli==1.2.3
      - traitlets==4.3.3
      - twine==1.8.1
      - urllib3==1.26.20
      - urwid==2.1.2
      - virtualenv==20.17.1
      - virtualenv-clone==0.5.7
      - virtualenvwrapper==4.8.4
      - wcwidth==0.2.13
prefix: /opt/conda/envs/polygraph

polygraph/types/tests/test_types.py::NonNullTest::test_square_bracket_notation polygraph/types/tests/test_types.py::ListTest::test_square_bracket_notation polygraph/types/tests/test_union.py::UnionTypeTest::test_square_bracket_notation
polygraph/types/tests/test_types.py::TypeMetaTest::test_scalar_meta polygraph/types/tests/test_types.py::TypeMetaTest::test_type_string polygraph/types/tests/test_types.py::NonNullTest::test_cannot_have_nonnull_of_nonnull polygraph/types/tests/test_types.py::NonNullTest::test_nonnull_accepts_values polygraph/types/tests/test_types.py::NonNullTest::test_nonnull_doesnt_accept_none polygraph/types/tests/test_types.py::NonNullTest::test_string polygraph/types/tests/test_types.py::ListTest::test_list_of_nonnulls polygraph/types/tests/test_types.py::ListTest::test_scalar_list polygraph/types/tests/test_union.py::UnionTypeTest::test_associativity polygraph/types/tests/test_union.py::UnionTypeTest::test_commutativity polygraph/types/tests/test_union.py::UnionTypeTest::test_pipe_operator polygraph/types/tests/test_union.py::UnionTypeTest::test_pipe_operator_with_more_than_two_types polygraph/types/tests/test_union.py::UnionValueTest::test_valid_type polygraph/types/tests/test_union.py::UnionValueTest::test_value_must_be_typed polygraph/types/tests/test_union.py::UnionValueTest::test_value_must_have_right_type
polygraph/types/type_builder.py
polygraph/types/type_builder.py