diff --git a/js/src/devtools/automation/arm64-jstests-slow.txt b/js/src/devtools/automation/arm64-jstests-slow.txt
new file mode 100644
index 000000000000..8f1068d541aa
--- /dev/null
+++ b/js/src/devtools/automation/arm64-jstests-slow.txt
@@ -0,0 +1,52 @@
+ecma/Date/15.9.5.10-2.js
+ecma/Date/15.9.5.11-2.js
+ecma/Date/15.9.5.12-2.js
+ecma/Date/15.9.5.8.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-01-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-02-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-03-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-04-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-05-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-06-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-07-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-08-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-09-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-10-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-11-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-12-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-13-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-14-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-15-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-16-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-17-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-18-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-19-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-20-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-21-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-22-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-23-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-24-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-25-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-26-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-27-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-30-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-31-of-32.js
+ecma_5/Object/15.2.3.6-dictionary-redefinition-32-of-32.js
+ecma_5/Object/15.2.3.6-middle-redefinition-1-of-8.js
+ecma_5/Object/15.2.3.6-middle-redefinition-2-of-8.js
+ecma_5/Object/15.2.3.6-middle-redefinition-3-of-8.js
+ecma_5/Object/15.2.3.6-middle-redefinition-4-of-8.js
+ecma_5/Object/15.2.3.6-middle-redefinition-5-of-8.js
+ecma_5/Object/15.2.3.6-middle-redefinition-6-of-8.js
+ecma_5/Object/15.2.3.6-middle-redefinition-7-of-8.js
+ecma_5/Object/15.2.3.6-middle-redefinition-8-of-8.js
+ecma_5/Object/15.2.3.6-redefinition-1-of-4.js
+ecma_5/Object/15.2.3.6-redefinition-2-of-4.js
+ecma_5/Object/15.2.3.6-redefinition-3-of-4.js
+ecma_5/Object/15.2.3.6-redefinition-4-of-4.js
+ecma_6/Comprehensions/sudoku.js
+js1_8/extensions/regress-476427.js
+js1_8_5/extensions/clone-complex-object.js
+js1_8_5/reflect-parse/classes.js
+js1_8_5/reflect-parse/destructuring-variable-declarations.js
+js1_8_5/regress/no-array-comprehension-length-limit.js
diff --git a/js/src/devtools/automation/autospider.sh b/js/src/devtools/automation/autospider.sh
index 4481843d28d9..c93dbb7dfe3e 100755
--- a/js/src/devtools/automation/autospider.sh
+++ b/js/src/devtools/automation/autospider.sh
@@ -217,10 +217,10 @@ elif [[ "$VARIANT" = "arm-sim" ||
         "$VARIANT" = "plaindebug" ]]; then
     export JSTESTS_EXTRA_ARGS=--jitflags=debug
 elif [[ "$VARIANT" = arm64* ]]; then
-    # The ARM64 JIT is not yet fully functional, and asm.js does not work.
-    # Just run "make check" and jsapi-tests.
-    RUN_JITTEST=false
-    RUN_JSTESTS=false
+    # The ARM64 simulator is slow, so some tests are timing out.
+    # Run a reduced set of test cases so this doesn't take hours.
+    export JSTESTS_EXTRA_ARGS="--exclude-file=$ABSDIR/arm64-jstests-slow.txt"
+    export JITTEST_EXTRA_ARGS="--jitflags=none --args=--baseline-eager -x ion/ -x asm.js/"
 fi
 
 $COMMAND_PREFIX $MAKE check || exit 1