diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 143ccdc..543f92e 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -26,6 +26,7 @@ jobs:
           - '3.12'
           - '3.13'
           - '3.14'
+          - '3.15'
           - 'pypy-3.10'
           - 'pypy-3.11'
         toxenv: [py]
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5c8e574..88516e4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+v0.3.0 (in development)
+-----------------------
+- Support Python 3.15
+
 v0.2.3 (2025-11-29)
 -------------------
 - Remove unused `typing_extensions` dependency
diff --git a/pyproject.toml b/pyproject.toml
index 5ea0d67..13c22ae 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -33,6 +33,7 @@ classifiers = [
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
     "Programming Language :: Python :: 3.14",
+    "Programming Language :: Python :: 3.15",
     "Programming Language :: Python :: Implementation :: CPython",
     "Programming Language :: Python :: Implementation :: PyPy",
     "Intended Audience :: Developers",
diff --git a/src/mailbits/__init__.py b/src/mailbits/__init__.py
index 183ee15..648a085 100644
--- a/src/mailbits/__init__.py
+++ b/src/mailbits/__init__.py
@@ -12,7 +12,7 @@
 Visit <https://github.com/jwodder/mailbits> for more information.
 """
 
-__version__ = "0.2.3"
+__version__ = "0.3.0.dev1"
 __author__ = "John Thorvald Wodder II"
 __author_email__ = "mailbits@varonathe.org"
 __license__ = "MIT"
diff --git a/tox.ini b/tox.ini
index 8620e72..c30f7f5 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = lint,typing,py310,py311,py312,py313,py314,pypy3
+envlist = lint,typing,py310,py311,py312,py313,py314,py315,pypy3
 skip_missing_interpreters = True
 isolated_build = True
 minversion = 3.3.0