diff --git a/pre_commit/prefixed_command_runner.py b/pre_commit/prefixed_command_runner.py
index d079d7ea..0b3012c1 100644
--- a/pre_commit/prefixed_command_runner.py
+++ b/pre_commit/prefixed_command_runner.py
@@ -33,10 +33,13 @@ class PrefixedCommandRunner(object):
 
         return proc.returncode, stdout, stderr
 
+    def path(self, path_end):
+        path = os.path.join(self.prefix_dir, path_end)
+        return os.path.normpath(path)
+
     @classmethod
-    def from_command_runner(cls, command_runner, prefix_postfix):
+    def from_command_runner(cls, command_runner, path_end):
         """Constructs a new command runner from an existing one by appending
-        `prefix_postfix` to the command runner's prefix directory.
+        `path_end` to the command runner's prefix directory.
         """
-        new_prefix = os.path.join(command_runner.prefix_dir, prefix_postfix)
-        return cls(new_prefix, popen=command_runner.__popen)
+        return cls(command_runner.path(path_end), popen=command_runner.__popen)
diff --git a/pre_commit/runner.py b/pre_commit/runner.py
index 0c17cd76..b7263356 100644
--- a/pre_commit/runner.py
+++ b/pre_commit/runner.py
@@ -5,6 +5,7 @@ import os.path
 import pre_commit.constants as C
 from pre_commit import git
 from pre_commit.clientlib.validate_config import load_config
+from pre_commit.prefixed_command_runner import PrefixedCommandRunner
 from pre_commit.repository import Repository
 from pre_commit.util import cached_property
 
@@ -44,3 +45,7 @@ class Runner(object):
     @cached_property
     def pre_commit_path(self):
         return os.path.join(self.git_root, '.git/hooks/pre-commit')
+
+    @cached_property
+    def workspace_runner(self):
+        return PrefixedCommandRunner(C.HOOKS_WORKSPACE)
diff --git a/tests/prefixed_command_runner_test.py b/tests/prefixed_command_runner_test.py
index 33100c69..630d8a4a 100644
--- a/tests/prefixed_command_runner_test.py
+++ b/tests/prefixed_command_runner_test.py
@@ -1,4 +1,5 @@
 
+import os
 import mock
 import pytest
 import subprocess
@@ -55,14 +56,31 @@ def test_run_substitutes_prefix(popen_mock):
     )
 
 
-@pytest.mark.parametrize(('first_prefix', 'postfix', 'expected_output'), (
-    ('foo', '', 'foo/'),
-    ('foo', 'bar', 'foo/bar/'),
-    ('./', 'bar', './bar/'),
-))
-def test_from_command_runner(first_prefix, postfix, expected_output):
-    first = PrefixedCommandRunner(first_prefix)
-    second = PrefixedCommandRunner.from_command_runner(first, postfix)
+PATH_TESTS = (
+    ('foo', '', 'foo'),
+    ('foo', 'bar', 'foo/bar'),
+    ('foo/bar', '../baz', 'foo/baz'),
+    ('./', 'bar', 'bar'),
+    ('./', '', '.'),
+)
+
+
+@pytest.mark.parametrize(('prefix', 'path_end', 'expected_output'), PATH_TESTS)
+def test_path(prefix, path_end, expected_output):
+    instance = PrefixedCommandRunner(prefix)
+    ret = instance.path(path_end)
+    assert ret == expected_output
+
+
+@pytest.mark.parametrize(('prefix', 'path_end', 'expected_output'),
+    tuple(
+        (prefix, path_end, expected_output + os.sep)
+        for prefix, path_end, expected_output in PATH_TESTS
+    ),
+)
+def test_from_command_runner(prefix, path_end, expected_output):
+    first = PrefixedCommandRunner(prefix)
+    second = PrefixedCommandRunner.from_command_runner(first, path_end)
     assert second.prefix_dir == expected_output
 
 
diff --git a/tests/runner_test.py b/tests/runner_test.py
index 167b7bb6..beac918e 100644
--- a/tests/runner_test.py
+++ b/tests/runner_test.py
@@ -59,3 +59,9 @@ def test_pre_commit_path():
     runner = Runner('foo/bar')
     expected_path = os.path.join('foo/bar', '.git/hooks/pre-commit')
     assert runner.pre_commit_path == expected_path
+
+
+def test_workspace_runneR():
+    runner = Runner('foo/bar')
+    ret = runner.workspace_runner
+    assert ret.prefix_dir == C.HOOKS_WORKSPACE + '/'