diff --git a/taskcluster/ci/openh264-plugin/kind.yml b/taskcluster/ci/openh264-plugin/kind.yml
index e14288a79fa5..eda4e591c794 100644
--- a/taskcluster/ci/openh264-plugin/kind.yml
+++ b/taskcluster/ci/openh264-plugin/kind.yml
@@ -97,6 +97,30 @@ jobs:
                 - linux64-cctools-port
                 - linux64-clang
                 - linux64-dump-syms
+    macosx64-aarch64/opt:
+        attributes:
+            build_platform: macosx64-aarch64
+            build_type: opt
+        treeherder:
+            platform: macosx64-aarch64/opt
+        worker-type: b-linux
+        worker:
+            max-run-time: 1800
+            artifacts:
+                - name: private/openh264
+                  path: /builds/worker/workspace/openh264/artifacts
+                  type: directory
+        run:
+            using: mozharness
+            script: mozharness/scripts/openh264_build.py
+            config:
+                - openh264/macosx64-aarch64.py
+        fetches:
+            toolchain:
+                - linux64-cctools-port
+                - linux64-clang
+                - linux64-dump-syms
+                - macosx64-sdk-11.0
     win32/opt:
         attributes:
             build_platform: win32
diff --git a/testing/mozharness/configs/openh264/macosx64-aarch64.py b/testing/mozharness/configs/openh264/macosx64-aarch64.py
new file mode 100644
index 000000000000..e5fc2c5e92aa
--- /dev/null
+++ b/testing/mozharness/configs/openh264/macosx64-aarch64.py
@@ -0,0 +1,42 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import os
+
+import mozharness
+
+external_tools_path = os.path.join(
+    os.path.abspath(os.path.dirname(os.path.dirname(mozharness.__file__))),
+    "external_tools",
+)
+
+config = {
+    "exes": {
+        "gittool.py": [os.path.join(external_tools_path, "gittool.py")],
+        "python2.7": "python2.7",
+    },
+    "dump_syms_binary": "{}/dump_syms/dump_syms".format(os.environ["MOZ_FETCHES_DIR"]),
+    "arch": "aarch64",
+    "use_yasm": True,
+    "operating_system": "darwin",
+    "partial_env": {
+        "CFLAGS": (
+            "-target aarch64-apple-darwin -mcpu=apple-a12 "
+            "-isysroot {MOZ_FETCHES_DIR}/MacOSX11.0.sdk".format(
+                MOZ_FETCHES_DIR=os.environ["MOZ_FETCHES_DIR"]
+            )
+        ),
+        "LDFLAGS": (
+            "-target aarch64-apple-darwin -mcpu=apple-a12 "
+            "-isysroot {MOZ_FETCHES_DIR}/MacOSX11.0.sdk".format(
+                MOZ_FETCHES_DIR=os.environ["MOZ_FETCHES_DIR"]
+            )
+        ),
+        "PATH": (
+            "{MOZ_FETCHES_DIR}/clang/bin/:{MOZ_FETCHES_DIR}/cctools/bin/:%(PATH)s".format(
+                MOZ_FETCHES_DIR=os.environ["MOZ_FETCHES_DIR"]
+            )
+        ),
+    },
+}
diff --git a/testing/mozharness/scripts/openh264_build.py b/testing/mozharness/scripts/openh264_build.py
index 6d1fd804325e..e0810f06a929 100755
--- a/testing/mozharness/scripts/openh264_build.py
+++ b/testing/mozharness/scripts/openh264_build.py
@@ -177,7 +177,7 @@ class OpenH264Build(TransferMixin, VCSScript, TooltoolMixin):
             self.error("missing a required key.")
 
     def query_package_name(self):
-        if self.config["arch"] == "x64":
+        if self.config["arch"] in ("x64", "aarch64"):
             bits = "64"
         else:
             bits = "32"
@@ -189,8 +189,11 @@ class OpenH264Build(TransferMixin, VCSScript, TooltoolMixin):
                     version=version, arch=self.config["arch"]
                 )
             elif self.config.get("operating_system") == "darwin":
-                return "openh264-macosx{bits}-{version}.zip".format(
-                    version=version, bits=bits
+                suffix = ""
+                if self.config["arch"] != "x64":
+                    suffix = "-" + self.config["arch"]
+                return "openh264-macosx{bits}{suffix}-{version}.zip".format(
+                    version=version, bits=bits, suffix=suffix
                 )
             else:
                 return "openh264-linux{bits}-{version}.zip".format(
@@ -218,15 +221,18 @@ class OpenH264Build(TransferMixin, VCSScript, TooltoolMixin):
         else:
             retval.append("ENABLE64BIT=No")
 
+        if self.config["arch"] == "x86":
+            retval.append("ARCH=x86")
+        elif self.config["arch"] == "x64":
+            retval.append("ARCH=x86_64")
+        elif self.config["arch"] == "aarch64":
+            retval.append("ARCH=arm64")
+        else:
+            self.fatal("Unknown arch: {}".format(self.config["arch"]))
+
         if "operating_system" in self.config:
             retval.append("OS=%s" % self.config["operating_system"])
             if self.config["operating_system"] == "android":
-                if self.config["arch"] == "x86":
-                    retval.append("ARCH=x86")
-                elif self.config["arch"] == "aarch64":
-                    retval.append("ARCH=arm64")
-                else:
-                    retval.append("ARCH=arm")
                 retval.append("TARGET=invalid")
                 retval.append("NDKLEVEL=%s" % self.config["min_sdk"])
                 retval.append("NDKROOT=%s/android-ndk" % os.environ["MOZ_FETCHES_DIR"])
@@ -242,14 +248,10 @@ class OpenH264Build(TransferMixin, VCSScript, TooltoolMixin):
             retval.append("CC=clang-cl")
             retval.append("CXX=clang-cl")
             if self.config["arch"] == "x86":
-                retval.append("ARCH=x86")
                 retval.append("CFLAGS=-m32")
             elif self.config["arch"] == "aarch64":
-                retval.append("ARCH=arm64")
                 retval.append("CFLAGS=--target=aarch64-windows-msvc")
                 retval.append("CXX_LINK_O=-nologo --target=aarch64-windows-msvc -Fe$@")
-            else:
-                retval.append("ARCH=x86_64")
         else:
             retval.append("CC=clang")
             retval.append("CXX=clang++")