diff --git a/.github/workflows/test-ci.yml b/.github/workflows/test-ci.yml
index ec6f3791..19881858 100644
--- a/.github/workflows/test-ci.yml
+++ b/.github/workflows/test-ci.yml
@@ -14,7 +14,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: [3.5, 3.6, 3.7, 3.8, 3.9]
+        python-version: [3.6, 3.7, 3.8, 3.9]
     runs-on: ${{ matrix.os }}
 
     steps:
diff --git a/main.py b/main.py
index e399ddce..1f3a7683 100755
--- a/main.py
+++ b/main.py
@@ -71,7 +71,7 @@ from subcmds import all_commands
 #
 # python-3.6 is in Ubuntu Bionic.
 MIN_PYTHON_VERSION_SOFT = (3, 6)
-MIN_PYTHON_VERSION_HARD = (3, 5)
+MIN_PYTHON_VERSION_HARD = (3, 6)
 
 if sys.version_info.major < 3:
   print('repo: error: Python 2 is no longer supported; '
diff --git a/requirements.json b/requirements.json
index 86b9a46c..cb55cd25 100644
--- a/requirements.json
+++ b/requirements.json
@@ -38,9 +38,9 @@
   # Supported Python versions.
   #
   # python-3.6 is in Ubuntu Bionic.
-  # python-3.5 is in Debian Stretch.
+  # python-3.7 is in Debian Buster.
   "python": {
-    "hard": [3, 5],
+    "hard": [3, 6],
     "soft": [3, 6]
   },
 
diff --git a/setup.py b/setup.py
index 9d0ff5f9..17aeae22 100755
--- a/setup.py
+++ b/setup.py
@@ -56,6 +56,6 @@ setuptools.setup(
         'Programming Language :: Python :: 3 :: Only',
         'Topic :: Software Development :: Version Control :: Git',
     ],
-    python_requires='>=3.5',
+    python_requires='>=3.6',
     packages=['subcmds'],
 )
diff --git a/tox.ini b/tox.ini
index 3282de14..aa4e2979 100644
--- a/tox.ini
+++ b/tox.ini
@@ -15,11 +15,10 @@
 # https://tox.readthedocs.io/
 
 [tox]
-envlist = py35, py36, py37, py38, py39
+envlist = py36, py37, py38, py39
 
 [gh-actions]
 python =
-    3.5: py35
     3.6: py36
     3.7: py37
     3.8: py38