diff --git a/fetch b/fetch
index 96e984a3e..4f0065b3d 100755
--- a/fetch
+++ b/fetch
@@ -16,6 +16,6 @@ elif [[ $GCLIENT_PY3 == 0 ]]; then
   # Explicitly run on Python 2
   PYTHONDONTWRITEBYTECODE=1 exec vpython "$base_dir/fetch.py" "$@"
 else
-  # Run on Python 2 for now, allows default to be flipped.
-  PYTHONDONTWRITEBYTECODE=1 exec vpython "$base_dir/fetch.py" "$@"
+  # Run on Python 3, allows default to be flipped.
+  PYTHONDONTWRITEBYTECODE=1 exec vpython3 "$base_dir/fetch.py" "$@"
 fi
diff --git a/gclient b/gclient
index 1dfb7f6c1..cb1d46787 100755
--- a/gclient
+++ b/gclient
@@ -33,6 +33,6 @@ elif [[ $GCLIENT_PY3 == 0 ]]; then
   # Explicitly run on Python 2
   PYTHONDONTWRITEBYTECODE=1 exec vpython "$base_dir/gclient.py" "$@"
 else
-  # Run on Python 2 for now, allows default to be flipped.
-  PYTHONDONTWRITEBYTECODE=1 exec vpython "$base_dir/gclient.py" "$@"
+  # Run on Python 3, allows default to be flipped.
+  PYTHONDONTWRITEBYTECODE=1 exec vpython3 "$base_dir/gclient.py" "$@"
 fi
diff --git a/python_runner.sh b/python_runner.sh
index 21996662c..adb46392a 100755
--- a/python_runner.sh
+++ b/python_runner.sh
@@ -59,6 +59,6 @@ elif [[ $GCLIENT_PY3 = 0 ]]; then
   # Explicitly run on Python 2
   vpython "$DEPOT_TOOLS/$SCRIPT" "$@"
 else
-  # Run on Python 2 for now, allows default to be flipped.
-  vpython "$DEPOT_TOOLS/$SCRIPT" "$@"
+  # Run on Python 3, allows default to be flipped.
+  vpython3 "$DEPOT_TOOLS/$SCRIPT" "$@"
 fi
diff --git a/roll-dep b/roll-dep
index 9a14ae45d..a471d22be 100755
--- a/roll-dep
+++ b/roll-dep
@@ -16,6 +16,6 @@ elif [[ $GCLIENT_PY3 = 0 ]]; then
   # Explicitly run on Python 2
   PYTHONDONTWRITEBYTECODE=1 exec vpython "$base_dir/roll_dep.py" "$@"
 else
-  # Run on Python 2 for now, allows default to be flipped.
-  PYTHONDONTWRITEBYTECODE=1 exec vpython "$base_dir/roll_dep.py" "$@"
+  # Run on Python 3, allows default to be flipped.
+  PYTHONDONTWRITEBYTECODE=1 exec vpython3 "$base_dir/roll_dep.py" "$@"
 fi
diff --git a/tests/gclient_smoketest.py b/tests/gclient_smoketest.py
index 9d4ea1a68..1a916de3c 100755
--- a/tests/gclient_smoketest.py
+++ b/tests/gclient_smoketest.py
@@ -40,6 +40,7 @@ class GClientSmokeBase(fake_repos.FakeReposTestBase):
     self.env['DEPOT_TOOLS_METRICS'] = '0'
     # Suppress Python 3 warnings and other test undesirables.
     self.env['GCLIENT_TEST'] = '1'
+    self.env['GCLIENT_PY3'] = '0' if sys.version_info.major == 2 else '1'
     self.maxDiff = None
 
   def gclient(self, cmd, cwd=None, error_ok=False):