diff --git a/tools/run-tests.py b/tools/run-tests.py
index cfca80f64b..61f91f0a5e 100755
--- a/tools/run-tests.py
+++ b/tools/run-tests.py
@@ -173,6 +173,8 @@ def BuildOptions():
                     help=("Quick check mode (skip slow/flaky tests)"))
   result.add_option("--report", help="Print a summary of the tests to be run",
                     default=False, action="store_true")
+  result.add_option("--json-test-results",
+                    help="Path to a file for storing json results.")
   result.add_option("--shard-count",
                     help="Split testsuites into this number of shards",
                     default=1, type="int")
@@ -463,6 +465,9 @@ def Execute(arch, mode, args, options, suites, workspace):
   if options.junitout:
     progress_indicator = progress.JUnitTestProgressIndicator(
         progress_indicator, options.junitout, options.junittestsuite)
+  if options.json_test_results:
+    progress_indicator = progress.JsonTestProgressIndicator(
+        progress_indicator, options.json_test_results, arch, mode)
 
   run_networked = not options.no_network
   if not run_networked:
diff --git a/tools/testrunner/local/progress.py b/tools/testrunner/local/progress.py
index 03116ee768..870dcc6b0b 100644
--- a/tools/testrunner/local/progress.py
+++ b/tools/testrunner/local/progress.py
@@ -26,11 +26,17 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
+import json
+import os
 import sys
 import time
 
 from . import junit_output
 
+
+ABS_PATH_PREFIX = os.getcwd() + os.sep
+
+
 def EscapeCommand(command):
   parts = []
   for part in command:
@@ -277,6 +283,55 @@ class JUnitTestProgressIndicator(ProgressIndicator):
         fail_text)
 
 
+class JsonTestProgressIndicator(ProgressIndicator):
+
+  def __init__(self, progress_indicator, json_test_results, arch, mode):
+    self.progress_indicator = progress_indicator
+    self.json_test_results = json_test_results
+    self.arch = arch
+    self.mode = mode
+    self.results = []
+
+  def Starting(self):
+    self.progress_indicator.runner = self.runner
+    self.progress_indicator.Starting()
+
+  def Done(self):
+    self.progress_indicator.Done()
+    complete_results = []
+    if os.path.exists(self.json_test_results):
+      with open(self.json_test_results, "r") as f:
+        # Buildbot might start out with an empty file.
+        complete_results = json.loads(f.read() or "[]")
+
+    complete_results.append({
+      "arch": self.arch,
+      "mode": self.mode,
+      "results": self.results,
+    })
+
+    with open(self.json_test_results, "w") as f:
+      f.write(json.dumps(complete_results))
+
+  def AboutToRun(self, test):
+    self.progress_indicator.AboutToRun(test)
+
+  def HasRun(self, test, has_unexpected_output):
+    self.progress_indicator.HasRun(test, has_unexpected_output)
+    if not has_unexpected_output:
+      return
+    self.results.append({
+      "name": test.GetLabel(),
+      "flags": test.flags,
+      "command": EscapeCommand(self.runner.GetCommand(test)).replace(
+          ABS_PATH_PREFIX, ""),
+      "stdout": test.output.stdout,
+      "stderr": test.output.stderr,
+      "exit_code": test.output.exit_code,
+      "result": "CRASH" if test.output.HasCrashed() else "FAIL",
+    })
+
+
 PROGRESS_INDICATORS = {
   'verbose': VerboseProgressIndicator,
   'dots': DotsProgressIndicator,