diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index dfd6d0b..b074d88 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -49,6 +49,12 @@ jobs:
             - os: ubuntu-latest
               python-version: '3.14'
               toxenv: py314
+            - os: ubuntu-latest
+              python-version: '3.15-dev'
+              toxenv: py315
+              # 3.15 is not released yet, so do not fail the whole matrix if it
+              # (or a dependency not having wheels for it yet) breaks.
+              allow-failure: true
             - os: macos-latest
               python-version: '3.12'
               toxenv: py312
diff --git a/docs/changes.rst b/docs/changes.rst
index a867cfc..67dc4f9 100644
--- a/docs/changes.rst
+++ b/docs/changes.rst
@@ -31,6 +31,12 @@ Fixes:
   conf.py now falls back to the setuptools_scm generated src/borgstore/_version.py
   and, if that is not there either, to an empty version.
 
+Other changes:
+
+- add support for Python 3.15: classifier, tox py315 env and a CI job running
+  the test suite on 3.15-dev. As 3.15 is not released yet, that CI job is
+  allowed to fail.
+
 
 Version 0.5.5 (2026-07-10)
 --------------------------
diff --git a/pyproject.toml b/pyproject.toml
index cde9444..48dd72d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -15,6 +15,7 @@ classifiers = [
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
     "Programming Language :: Python :: 3.14",
+    "Programming Language :: Python :: 3.15",
     "Topic :: Software Development :: Libraries",
     "Topic :: Software Development :: Libraries :: Python Modules",
 ]
diff --git a/tox.ini b/tox.ini
index ef3df51..83307ee 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,7 +1,7 @@
 # tox configuration - if you change anything here, run this to verify: tox --recreate
 
 [tox]
-envlist = py{311,312,313,314},flake8,mypy
+envlist = py{311,312,313,314,315},flake8,mypy
 
 [testenv]
 deps =