diff --git a/tools/releasetools/apex_utils.py b/tools/releasetools/apex_utils.py
index 113f78b..cf10386 100644
--- a/tools/releasetools/apex_utils.py
+++ b/tools/releasetools/apex_utils.py
@@ -133,7 +133,6 @@
     arguments_dict = {
         'manifest': os.path.join(apex_dir, 'apex_manifest.pb'),
         'build_info': os.path.join(apex_dir, 'apex_build_info.pb'),
-        'assets_dir': os.path.join(apex_dir, 'assets'),
         'android_jar_path': android_jar_path,
         'key': payload_key,
         'pubkey': payload_public_key,
@@ -156,10 +155,16 @@
     for key, val in arguments_dict.items():
       repack_cmd.append('--' + key)
       repack_cmd.append(val)
+    # optional arguments for apex repacking
     manifest_json = os.path.join(apex_dir, 'apex_manifest.json')
     if os.path.exists(manifest_json):
       repack_cmd.append('--manifest_json')
       repack_cmd.append(manifest_json)
+    assets_dir = os.path.join(apex_dir, 'assets')
+    if os.path.isdir(assets_dir):
+      repack_cmd.append('--assets_dir')
+      repack_cmd.append(assets_dir)
+
     repack_cmd.append(payload_dir)
     repack_cmd.append(repacked_apex)
     common.RunAndCheckOutput(repack_cmd)
diff --git a/tools/releasetools/test_apex_utils.py b/tools/releasetools/test_apex_utils.py
index df61ac0..cc28f3f 100644
--- a/tools/releasetools/test_apex_utils.py
+++ b/tools/releasetools/test_apex_utils.py
@@ -16,6 +16,7 @@
 
 import os
 import os.path
+import zipfile
 
 import apex_utils
 import common
@@ -155,3 +156,23 @@
     payload_pubkey = common.ExtractAvbPublicKey('avbtool',
                                                 self.payload_key)
     signer.ProcessApexFile(apk_keys, self.payload_key, payload_pubkey)
+
+  @test_utils.SkipIfExternalToolsUnavailable()
+  def test_ApexApkSigner_noAssetDir(self):
+    apex_path = os.path.join(self.testdata_dir, 'has_apk.apex')
+    no_asset = common.MakeTempFile(suffix='.apex')
+    with zipfile.ZipFile(no_asset, 'w') as output_zip:
+      with zipfile.ZipFile(apex_path, 'r') as input_zip:
+        name_list = input_zip.namelist()
+        for name in name_list:
+          if not name.startswith('assets'):
+            output_zip.writestr(name, input_zip.read(name))
+
+    signer = apex_utils.ApexApkSigner(no_asset, None, None)
+    apk_keys = {'wifi-service-resources.apk': os.path.join(
+        self.testdata_dir, 'testkey')}
+
+    self.payload_key = os.path.join(self.testdata_dir, 'testkey_RSA4096.key')
+    payload_pubkey = common.ExtractAvbPublicKey('avbtool',
+                                                self.payload_key)
+    signer.ProcessApexFile(apk_keys, self.payload_key, payload_pubkey)