diff --git a/js/src/devtools/automation/variants/tsan b/js/src/devtools/automation/variants/tsan
index 8f9ee8e63881..abffb764e283 100644
--- a/js/src/devtools/automation/variants/tsan
+++ b/js/src/devtools/automation/variants/tsan
@@ -5,7 +5,7 @@
     "compiler": "clang",
     "env": {
         "LLVM_SYMBOLIZER": "{TOOLTOOL_CHECKOUT}/clang/bin/llvm-symbolizer",
-        "JITTEST_EXTRA_ARGS": "--jitflags=debug --ignore-timeouts={DIR}/cgc-jittest-timeouts.txt --unusable-error-status",
+        "JITTEST_EXTRA_ARGS": "--jitflags=tsan --ignore-timeouts={DIR}/cgc-jittest-timeouts.txt --unusable-error-status",
         "JSTESTS_EXTRA_ARGS": "--exclude-file={DIR}/cgc-jstests-slow.txt",
         "TSAN_OPTIONS": "exitcode=0 log_path={OUTDIR}/sanitize_log"
     },
diff --git a/js/src/tests/lib/tests.py b/js/src/tests/lib/tests.py
index 67b8233eb235..cea2bcb3cd1a 100644
--- a/js/src/tests/lib/tests.py
+++ b/js/src/tests/lib/tests.py
@@ -32,6 +32,15 @@ JITFLAGS = {
         ['--ion-eager', '--ion-offthread-compile=off'], # implies --baseline-eager
         ['--baseline-eager'],
     ],
+    # Cover cases useful for tsan. Note that tsan on try messes up the signal
+    # handler (bug 1362239), so must avoid wasm/asmjs.
+    'tsan': [
+        ['--no-asmjs', '--no-wasm'],
+        ['--no-asmjs', '--no-wasm',
+         '--ion-eager', '--ion-offthread-compile=off', '--non-writable-jitcode',
+         '--ion-check-range-analysis', '--ion-extra-checks', '--no-sse3', '--no-threads'],
+        ['--no-asmjs', '--no-wasm', '--no-baseline', '--no-ion'],
+    ],
     # Interpreter-only, for tools that cannot handle binary code generation.
     'interp': [
         ['--no-baseline', '--no-asmjs', '--no-wasm', '--no-native-regexp']