diff --git a/rules_python/BUILD b/rules_python/BUILD
index 6c23e01ae7..734bd3a73b 100644
--- a/rules_python/BUILD
+++ b/rules_python/BUILD
@@ -21,6 +21,7 @@ load("@piptool_deps//:requirements.bzl", "requirement")
 py_library(
     name = "whl",
     srcs = ["whl.py"],
+    srcs_version = "PY3ONLY",
     deps = [
         requirement("setuptools"),
     ],
@@ -30,8 +31,8 @@ py_test(
     name = "whl_test",
     srcs = ["whl_test.py"],
     data = [
-        "@futures_3_1_1_whl//file",
         "@futures_2_2_0_whl//file",
+        "@futures_3_1_1_whl//file",
         "@google_cloud_language_whl//file",
         "@grpc_whl//file",
         "@mock_whl//file",
@@ -47,6 +48,7 @@ load("@subpar//:subpar.bzl", "par_binary")
 par_binary(
     name = "piptool",
     srcs = ["piptool.py"],
+    default_python_version = "PY3",
     deps = [
         ":whl",
         requirement("pip"),
@@ -57,6 +59,7 @@ par_binary(
 par_binary(
     name = "whltool",
     srcs = ["whl.py"],
+    default_python_version = "PY3",
     main = "whl.py",
     deps = [
         ":whl",
diff --git a/rules_python/whl.py b/rules_python/whl.py
index e3544d80d0..10a28e3601 100644
--- a/rules_python/whl.py
+++ b/rules_python/whl.py
@@ -18,6 +18,7 @@
 import os
 import pkg_resources
 import re
+import sys
 import zipfile
 
 
@@ -113,7 +114,7 @@ def _parse_metadata(self, content):
 
 
 parser = argparse.ArgumentParser(
-    description='Unpack a WHL file as a py_library.')
+    description='Unpack a WHL file as a py_library [Python {}]'.format(sys.version))
 
 parser.add_argument('--whl', action='store',
                     help=('The .whl file we are expanding.'))
diff --git a/tools/piptool.par b/tools/piptool.par
index b7a62c5563..1211d79a17 100755
Binary files a/tools/piptool.par and b/tools/piptool.par differ
diff --git a/tools/whltool.par b/tools/whltool.par
index 8e2f34250d..5d68b6913c 100755
Binary files a/tools/whltool.par and b/tools/whltool.par differ
diff --git a/update_tools.sh b/update_tools.sh
index 5f00e9c331..28fb48d7a7 100755
--- a/update_tools.sh
+++ b/update_tools.sh
@@ -16,6 +16,6 @@
 
 set -euo pipefail
 
-bazel build //rules_python:piptool.par //rules_python:whltool.par
+bazel build //rules_python:piptool.par //rules_python:whltool.par --force_python=PY3 --python_path=/usr/bin/python3
 cp bazel-bin/rules_python/piptool.par tools/piptool.par
 cp bazel-bin/rules_python/whltool.par tools/whltool.par