diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 2246a57..6b76f23 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -18,7 +18,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v6
         with:
-          python-version: '3.9'
+          python-version: '3.10'
 
       - name: Get pip cache dir
         id: pip-cache
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index b8a64fe..5bc3114 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -9,7 +9,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.10", "3.11", "3.12", "3.13"]
     steps:
       - uses: actions/checkout@v5
 
@@ -35,7 +35,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.10", "3.11", "3.12", "3.13"]
     services:
       postgres:
         image: postgres:15
@@ -81,7 +81,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.10", "3.11", "3.12", "3.13"]
     services:
       mysql:
         image: mysql:8.0
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index e57ca75..8b06b16 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -4,10 +4,10 @@ repos:
     rev: 25.9.0
     hooks:
       - id: black
-        language_version: python3.9
+        language_version: python3.10
         args:
           - "--target-version"
-          - "py39"
+          - "py310"
   - repo: https://github.com/PyCQA/flake8
     rev: "7.3.0"
     hooks:
@@ -21,7 +21,7 @@ repos:
     rev: v3.20.0
     hooks:
     -   id: pyupgrade
-        args: [--py39-plus]
+        args: [--py310-plus]
   - repo: https://github.com/adamchainz/django-upgrade
     rev: 1.29.0
     hooks:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index cc735ec..c32e105 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## Next Release
 
+#### Improvements
+
+- Drop 'Python 3.9' support ([#773](https://github.com/jazzband/django-auditlog/pull/773))
+
 ## 3.3.0 (2025-09-18)
 
 #### Improvements
diff --git a/auditlog/cid.py b/auditlog/cid.py
index 8d2aa9f..3e2b78f 100644
--- a/auditlog/cid.py
+++ b/auditlog/cid.py
@@ -1,5 +1,4 @@
 from contextvars import ContextVar
-from typing import Optional
 
 from django.conf import settings
 from django.http import HttpRequest
@@ -8,7 +7,7 @@ from django.utils.module_loading import import_string
 correlation_id = ContextVar("auditlog_correlation_id", default=None)
 
 
-def set_cid(request: Optional[HttpRequest] = None) -> None:
+def set_cid(request: HttpRequest | None = None) -> None:
     """
     A function to read the cid from a request.
     If the header is not in the request, then we set it to `None`.
@@ -40,11 +39,11 @@ def set_cid(request: Optional[HttpRequest] = None) -> None:
     correlation_id.set(cid)
 
 
-def _get_cid() -> Optional[str]:
+def _get_cid() -> str | None:
     return correlation_id.get()
 
 
-def get_cid() -> Optional[str]:
+def get_cid() -> str | None:
     """
     Calls the cid getter function based on `settings.AUDITLOG_CID_GETTER`
 
diff --git a/auditlog/diff.py b/auditlog/diff.py
index fc98987..72d1a76 100644
--- a/auditlog/diff.py
+++ b/auditlog/diff.py
@@ -1,6 +1,6 @@
 import json
+from collections.abc import Callable
 from datetime import timezone
-from typing import Callable, Optional
 
 from django.conf import settings
 from django.core.exceptions import ObjectDoesNotExist
@@ -131,7 +131,7 @@ def is_primitive(obj) -> bool:
     return isinstance(obj, primitive_types)
 
 
-def get_mask_function(mask_callable: Optional[str] = None) -> Callable[[str], str]:
+def get_mask_function(mask_callable: str | None = None) -> Callable[[str], str]:
     """
     Get the masking function to use based on the following priority:
     1. Model-specific mask_callable if provided
@@ -168,8 +168,8 @@ def mask_str(value: str) -> str:
 
 
 def model_instance_diff(
-    old: Optional[Model],
-    new: Optional[Model],
+    old: Model | None,
+    new: Model | None,
     fields_to_check=None,
     use_json_for_changes=False,
 ):
diff --git a/auditlog/middleware.py b/auditlog/middleware.py
index bd01da3..295448e 100644
--- a/auditlog/middleware.py
+++ b/auditlog/middleware.py
@@ -1,5 +1,3 @@
-from typing import Optional
-
 from django.conf import settings
 from django.contrib.auth import get_user_model
 
@@ -39,7 +37,7 @@ class AuditlogMiddleware:
         return remote_addr
 
     @staticmethod
-    def _get_remote_port(request) -> Optional[int]:
+    def _get_remote_port(request) -> int | None:
         remote_port = request.headers.get("X-Forwarded-Port", "")
 
         try:
diff --git a/auditlog/models.py b/auditlog/models.py
index 01b54a0..d73ecda 100644
--- a/auditlog/models.py
+++ b/auditlog/models.py
@@ -1,9 +1,10 @@
 import ast
 import contextlib
 import json
+from collections.abc import Callable
 from copy import deepcopy
 from datetime import timezone
-from typing import Any, Callable, Union
+from typing import Any
 
 from dateutil import parser
 from dateutil.tz import gettz
@@ -534,7 +535,7 @@ class LogEntry(models.Model):
         return changes_display_dict
 
     def _get_changes_display_for_fk_field(
-        self, field: Union[models.ForeignKey, models.OneToOneField], value: Any
+        self, field: models.ForeignKey | models.OneToOneField, value: Any
     ) -> str:
         """
         :return: A string representing a given FK value and the field to which it belongs
diff --git a/auditlog/registry.py b/auditlog/registry.py
index c8ca907..835acd1 100644
--- a/auditlog/registry.py
+++ b/auditlog/registry.py
@@ -1,7 +1,7 @@
 import copy
 from collections import defaultdict
-from collections.abc import Collection, Iterable
-from typing import Any, Callable, Optional, Union
+from collections.abc import Callable, Collection, Iterable
+from typing import Any
 
 from django.apps import apps
 from django.db.models import ManyToManyField, Model
@@ -38,7 +38,7 @@ class AuditlogModelRegistry:
         delete: bool = True,
         access: bool = True,
         m2m: bool = True,
-        custom: Optional[dict[ModelSignal, Callable]] = None,
+        custom: dict[ModelSignal, Callable] | None = None,
     ):
         from auditlog.receivers import log_access, log_create, log_delete, log_update
 
@@ -62,14 +62,14 @@ class AuditlogModelRegistry:
     def register(
         self,
         model: ModelBase = None,
-        include_fields: Optional[list[str]] = None,
-        exclude_fields: Optional[list[str]] = None,
-        mapping_fields: Optional[dict[str, str]] = None,
-        mask_fields: Optional[list[str]] = None,
-        mask_callable: Optional[str] = None,
-        m2m_fields: Optional[Collection[str]] = None,
+        include_fields: list[str] | None = None,
+        exclude_fields: list[str] | None = None,
+        mapping_fields: dict[str, str] | None = None,
+        mask_fields: list[str] | None = None,
+        mask_callable: str | None = None,
+        m2m_fields: Collection[str] | None = None,
         serialize_data: bool = False,
-        serialize_kwargs: Optional[dict[str, Any]] = None,
+        serialize_kwargs: dict[str, Any] | None = None,
         serialize_auditlog_fields_only: bool = False,
     ):
         """
@@ -259,7 +259,7 @@ class AuditlogModelRegistry:
         ]
         return exclude_models
 
-    def _register_models(self, models: Iterable[Union[str, dict[str, Any]]]) -> None:
+    def _register_models(self, models: Iterable[str | dict[str, Any]]) -> None:
         models = copy.deepcopy(models)
         for model in models:
             if isinstance(model, str):
diff --git a/docs/source/installation.rst b/docs/source/installation.rst
index 2a2c3c2..ab4d468 100644
--- a/docs/source/installation.rst
+++ b/docs/source/installation.rst
@@ -11,10 +11,10 @@ The repository can be found at https://github.com/jazzband/django-auditlog/.
 
 **Requirements**
 
-- Python 3.9 or higher
+- Python 3.10 or higher
 - Django 4.2, 5.0, 5.1, and 5.2
 
-Auditlog is currently tested with Python 3.9+ and Django 4.2, 5.0, 5.1, and 5.2. The latest test report can be found
+Auditlog is currently tested with Python 3.10+ and Django 4.2, 5.0, 5.1, and 5.2. The latest test report can be found
 at https://github.com/jazzband/django-auditlog/actions.
 
 Adding Auditlog to your Django application
diff --git a/setup.py b/setup.py
index 9147842..2f1cc5c 100644
--- a/setup.py
+++ b/setup.py
@@ -29,12 +29,11 @@ setup(
     description="Audit log app for Django",
     long_description=long_description,
     long_description_content_type="text/markdown",
-    python_requires=">=3.9",
+    python_requires=">=3.10",
     install_requires=["Django>=4.2", "python-dateutil>=2.7.0"],
     zip_safe=False,
     classifiers=[
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",
         "Programming Language :: Python :: 3.12",
diff --git a/tox.ini b/tox.ini
index e804268..a123535 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,13 +1,13 @@
 [tox]
 envlist =
-    {py39,py310,py311}-django42
+    {py310,py311}-django42
     {py310,py311,py312}-django50
     {py310,py311,py312,py313}-django51
     {py310,py311,py312,py313}-django52
     {py312,py313}-djangomain
-    py39-docs
-    py39-lint
-    py39-checkmigrations
+    py310-docs
+    py310-lint
+    py310-checkmigrations
 
 [testenv]
 setenv =
@@ -42,19 +42,18 @@ basepython =
     py312: python3.12
     py311: python3.11
     py310: python3.10
-    py39: python3.9
 
-[testenv:py39-docs]
+[testenv:py310-docs]
 changedir = docs/source
 deps = -rdocs/requirements.txt
 commands = sphinx-build -W -b html -d {envtmpdir}/doctrees . {envtmpdir}/html
 
-[testenv:py39-lint]
+[testenv:py310-lint]
 deps = pre-commit
 commands =
     pre-commit run --all-files
 
-[testenv:py39-checkmigrations]
+[testenv:py310-checkmigrations]
 description = Check for missing migrations
 changedir = auditlog_tests
 deps =
@@ -73,7 +72,6 @@ commands =
 
 [gh-actions]
 python =
-  3.9: py39
   3.10: py310
   3.11: py311
   3.12: py312