diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index c554ec875..b0421f8e4 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -11,7 +11,7 @@ jobs:
     strategy:
       matrix:
         python-version: ['3.14']
-        tmux-version: ['2.6', '2.7', '2.8', '3.0a', '3.1b', '3.2a', '3.3a', '3.4', '3.5', 'master']
+        tmux-version: ['2.6', '2.7', '2.8', '3.0a', '3.1b', '3.2a', '3.3a', '3.4', '3.5', '3.6', 'master']
     steps:
       - uses: actions/checkout@v5
 
diff --git a/CHANGES b/CHANGES
index 93b8c2836..dd4b1c328 100644
--- a/CHANGES
+++ b/CHANGES
@@ -34,6 +34,12 @@ $ uvx --from 'libtmux' --prerelease allow python
 
 - _Future release notes will be placed here_
 
+### What's new
+
+#### tmux 3.6 support (#607)
+
+Added tmux 3.6 to test grid and `TMUX_MAX_VERSION` 3.4 -> 3.6.
+
 ## libtmux 0.47.0 (2025-11-01)
 
 ### Breaking changes
diff --git a/src/libtmux/common.py b/src/libtmux/common.py
index ac9b9b7f1..886b160fb 100644
--- a/src/libtmux/common.py
+++ b/src/libtmux/common.py
@@ -27,7 +27,7 @@
 TMUX_MIN_VERSION = "1.8"
 
 #: Most recent version of tmux supported
-TMUX_MAX_VERSION = "3.4"
+TMUX_MAX_VERSION = "3.6"
 
 SessionDict = dict[str, t.Any]
 WindowDict = dict[str, t.Any]
diff --git a/tests/legacy_api/test_common.py b/tests/legacy_api/test_common.py
index fb32427e0..44c1742fb 100644
--- a/tests/legacy_api/test_common.py
+++ b/tests/legacy_api/test_common.py
@@ -54,7 +54,7 @@ def mock_tmux_cmd(*args: t.Any, **kwargs: t.Any) -> Hi:
 
 def test_allows_next_version(monkeypatch: pytest.MonkeyPatch) -> None:
     """Assert get_version() supports next version."""
-    TMUX_NEXT_VERSION = str(float(TMUX_MAX_VERSION) + 0.1)
+    TMUX_NEXT_VERSION = "3.7"
 
     class Hi:
         stdout: t.ClassVar = [f"tmux next-{TMUX_NEXT_VERSION}"]
diff --git a/tests/test_common.py b/tests/test_common.py
index 3d67182c1..3aa045bc4 100644
--- a/tests/test_common.py
+++ b/tests/test_common.py
@@ -298,10 +298,10 @@ class VersionParsingFixture(t.NamedTuple):
     ),
     VersionParsingFixture(
         test_id="next_version",
-        mock_stdout=[f"tmux next-{float(TMUX_MAX_VERSION) + 0.1!s}"],
+        mock_stdout=["tmux next-3.7"],
         mock_stderr=None,
         mock_platform=None,
-        expected_version=str(float(TMUX_MAX_VERSION) + 0.1),
+        expected_version="3.7",
         raises=False,
         exc_msg_regex=None,
     ),