diff --git a/test/cpp/interop/interop_client.cc b/test/cpp/interop/interop_client.cc
index effbb8a42eb391cc9b228493912ce41262096b6d..ffd19eb1d5f2611633a07150d0ff67d6115bcb13 100644
--- a/test/cpp/interop/interop_client.cc
+++ b/test/cpp/interop/interop_client.cc
@@ -988,8 +988,8 @@ bool InteropClient::DoUnimplementedMethod() {
   Empty response = Empty::default_instance();
   ClientContext context;
 
-  Status s = serviceStub_.Get()->UnimplementedMethod(
-    &context, request, &response);
+  Status s =
+      serviceStub_.Get()->UnimplementedMethod(&context, request, &response);
 
   if (!AssertStatusCode(s, StatusCode::UNIMPLEMENTED)) {
     return false;
diff --git a/tools/run_tests/filter_pull_request_tests.py b/tools/run_tests/filter_pull_request_tests.py
new file mode 100644
index 0000000000000000000000000000000000000000..55dab42f8a7a6afba1488a6e25cdecc7550bcf02
--- /dev/null
+++ b/tools/run_tests/filter_pull_request_tests.py
@@ -0,0 +1,184 @@
+#!/usr/bin/env python2.7
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Filter out tests based on file differences compared to merge target branch"""
+
+import re
+from subprocess import call, check_output
+
+
+class TestSuite:
+  """
+  Contains tag to identify job as belonging to this test suite and
+  triggers to identify if changed files are relevant
+  """
+  def __init__(self, tags):
+    """
+    Build TestSuite to group tests by their tags
+    :param tag: string used to identify if a job belongs to this TestSuite
+    todo(mattkwong): Change the use of tag because do not want to depend on
+    job.shortname to identify what suite a test belongs to
+    """
+    self.triggers = []
+    self.tags = tags
+
+  def add_trigger(self, trigger):
+    """
+    Add a regex to list of triggers that determine if a changed file should run tests
+    :param trigger: regex matching file relevant to tests
+    """
+    self.triggers.append(trigger)
+
+# Create test suites
+_core_test_suite = TestSuite(['_c_'])
+_cpp_test_suite = TestSuite(['_c++_'])
+_csharp_test_suite = TestSuite(['_csharp_'])
+_node_test_suite = TestSuite(['_node_'])
+_objc_test_suite = TestSuite(['_objc_'])
+_php_test_suite = TestSuite(['_php_', '_php7_'])
+_python_test_suite = TestSuite(['_python_'])
+_ruby_test_suite = TestSuite(['_ruby'])
+_all_test_suites = [_core_test_suite, _cpp_test_suite, _csharp_test_suite,
+                    _node_test_suite, _objc_test_suite, _php_test_suite,
+                    _python_test_suite, _ruby_test_suite]
+
+# Dictionary of whitelistable files where the key is a regex matching changed files
+# and the value is a list of tests that should be run. An empty list means that
+# the changed files should not trigger any tests. Any changed file that does not
+# match any of these regexes will trigger all tests
+_WHITELIST_DICT = {
+  '^templates/.*': [],
+  '^doc/.*': [],
+  '^examples/.*': [],
+  '^summerofcode/.*': [],
+  '.*README.md$': [],
+  '.*LICENSE$': [],
+  '^src/cpp.*': [_cpp_test_suite],
+  '^src/csharp.*': [_csharp_test_suite],
+  '^src/node.*': [_node_test_suite],
+  '^src/objective-c.*': [_objc_test_suite],
+  '^src/php.*': [_php_test_suite],
+  '^src/python.*': [_python_test_suite],
+  '^src/ruby.*': [_ruby_test_suite],
+  '^test/core.*': [_core_test_suite],
+  '^test/cpp.*': [_cpp_test_suite],
+  '^test/distrib/cpp.*': [_cpp_test_suite],
+  '^test/distrib/csharp.*': [_csharp_test_suite],
+  '^test/distrib/node.*': [_node_test_suite],
+  '^test/distrib/php.*': [_php_test_suite],
+  '^test/distrib/python.*': [_python_test_suite],
+  '^test/distrib/ruby.*': [_ruby_test_suite]
+}
+# Add all triggers to their respective test suites
+for trigger, test_suites in _WHITELIST_DICT.iteritems():
+  for test_suite in test_suites:
+    test_suite.add_trigger(trigger)
+
+
+def _get_changed_files(base_branch):
+  """
+  Get list of changed files between current branch and base of target merge branch
+  """
+  # git fetch might need to be called on Jenkins slave
+  # todo(mattkwong): remove or uncomment below after seeing if Jenkins needs this
+  # call(['git', 'fetch'])
+
+  # Get file changes between branch and merge-base of specified branch
+  # Not combined to be Windows friendly
+  base_commit = check_output(["git", "merge-base", base_branch, "HEAD"]).rstrip()
+  return check_output(["git", "diff", base_commit, "--name-only"]).splitlines()
+
+
+def _can_skip_tests(file_names, triggers):
+  """
+  Determines if tests are skippable based on if all files do not match list of regexes
+  :param file_names: list of changed files generated by _get_changed_files()
+  :param triggers: list of regexes matching file name that indicates tests should be run
+  :return: safe to skip tests
+  """
+  for file_name in file_names:
+    if any(re.match(trigger, file_name) for trigger in triggers):
+      return False
+  return True
+
+
+def _remove_irrelevant_tests(tests, tag):
+  """
+  Filters out tests by config or language - will not remove sanitizer tests
+  :param tests: list of all tests generated by run_tests_matrix.py
+  :param tag: string representing language or config to filter - "_(language)_" or "_(config)"
+  :return: list of relevant tests
+  """
+  # todo(mattkwong): find a more reliable way to filter tests - don't use shortname
+  return [test for test in tests if tag not in test.shortname or
+          any(san_tag in test.shortname for san_tag in ['_asan', '_tsan', '_msan'])]
+
+
+def _remove_sanitizer_tests(tests):
+  """
+  Filters out sanitizer tests
+  :param tests: list of all tests generated by run_tests_matrix.py
+  :return: list of relevant tests
+  """
+  # todo(mattkwong): find a more reliable way to filter tests - don't use shortname
+  return [test for test in tests if
+          all(san_tag not in test.shortname for san_tag in ['_asan', '_tsan', '_msan'])]
+
+
+def filter_tests(tests, base_branch):
+  """
+  Filters out tests that are safe to ignore
+  :param tests: list of all tests generated by run_tests_matrix.py
+  :return: list of relevant tests
+  """
+  print("Finding file differences between %s repo and current branch...\n" % base_branch)
+  changed_files = _get_changed_files(base_branch)
+  for changed_file in changed_files:
+    print(changed_file)
+  print
+
+  # Regex that combines all keys in _WHITELIST_DICT
+  all_triggers = "(" + ")|(".join(_WHITELIST_DICT.keys()) + ")"
+  # Check if all tests have to be run
+  for changed_file in changed_files:
+    if not re.match(all_triggers, changed_file):
+      return(tests)
+  # Filter out tests by language
+  for test_suite in _all_test_suites:
+    if _can_skip_tests(changed_files, test_suite.triggers):
+      for tag in test_suite.tags:
+        print("  Filtering %s tests" % tag)
+        tests = _remove_irrelevant_tests(tests, tag)
+  # Sanitizer tests skipped if core and c++ are skipped
+  if _can_skip_tests(changed_files, _cpp_test_suite.triggers + _core_test_suite.triggers):
+    print("  Filtering Sanitizer tests")
+    tests = _remove_sanitizer_tests(tests)
+
+  return tests
diff --git a/tools/run_tests/run_tests_matrix.py b/tools/run_tests/run_tests_matrix.py
index 60c21a1e218aada50f1bae617217c8b89cec74fb..21d3dd4a0bcacdca7451d550f888333aa55f4679 100755
--- a/tools/run_tests/run_tests_matrix.py
+++ b/tools/run_tests/run_tests_matrix.py
@@ -36,6 +36,7 @@ import multiprocessing
 import os
 import report_utils
 import sys
+from filter_pull_request_tests import filter_tests
 
 _ROOT = os.path.abspath(os.path.join(os.path.dirname(sys.argv[0]), '../..'))
 os.chdir(_ROOT)
@@ -231,6 +232,15 @@ argp.add_argument('--dry_run',
                   action='store_const',
                   const=True,
                   help='Only print what would be run.')
+argp.add_argument('--filter_pr_tests',
+	          default=False,
+		  action='store_const',	
+		  const=True,	  
+		  help='Filters out tests irrelavant to pull request changes.')
+argp.add_argument('--base_branch',
+                  default='origin/master',
+                  type=str,
+                  help='Branch that pull request is requesting to merge into')
 args = argp.parse_args()
 
 extra_args = []
@@ -264,6 +274,19 @@ for job in jobs:
     print '  %s' % job.shortname
 print
 
+if args.filter_pr_tests:
+  print 'IMPORTANT: Test filtering is not active; this is only for testing.'
+  relevant_jobs = filter_tests(jobs, args.base_branch)
+  # todo(mattkwong): add skipped tests to report.xml
+  print
+  if len(relevant_jobs) == len(jobs):
+    print '(TESTING) No tests will be skipped.'
+  else:
+    print '(TESTING) These tests will be skipped:'
+    for job in list(set(jobs) - set(relevant_jobs)):
+      print '  %s' % job.shortname
+  print
+
 if args.dry_run:
   print '--dry_run was used, exiting'
   sys.exit(1)