new file mode 100644
--- /dev/null
+++ b/mobile/android/config/mozconfigs/android-x86_64/debug
@@ -0,0 +1,16 @@
+. "$topsrcdir/mobile/android/config/mozconfigs/common"
+
+# Global options
+ac_add_options --enable-debug
+
+# Android
+ac_add_options --with-android-min-sdk=21
+ac_add_options --target=x86_64-linux-android
+
+export MOZILLA_OFFICIAL=1
+export MOZ_TELEMETRY_REPORTING=1
+export MOZ_ANDROID_POCKET
+
+ac_add_options --with-branding=mobile/android/branding/nightly
+
+. "$topsrcdir/mobile/android/config/mozconfigs/common.override"

new file mode 100644
--- /dev/null
+++ b/mobile/android/config/mozconfigs/android-x86_64/l10n-nightly
@@ -0,0 +1,24 @@
+NO_NDK=1
+
+. "$topsrcdir/mobile/android/config/mozconfigs/common"
+
+. "$topsrcdir/mobile/android/config/mozconfigs/android-x86_64/nightly"
+
+# L10n
+ac_add_options --with-l10n-base=../../l10n-central
+
+# Don't autoclobber l10n, as this can lead to missing binaries and broken builds
+# Bug 1283438
+mk_add_options AUTOCLOBBER=
+
+. "$topsrcdir/build/mozconfig.no-compile"
+
+# Global options
+ac_add_options --disable-tests
+ac_add_options --disable-nodejs
+unset NODEJS
+
+ac_add_options --enable-updater
+ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
+
+. "$topsrcdir/mobile/android/config/mozconfigs/common.override"

new file mode 100644
--- /dev/null
+++ b/mobile/android/config/mozconfigs/android-x86_64/nightly
@@ -0,0 +1,22 @@
+. "$topsrcdir/mobile/android/config/mozconfigs/common"
+
+# Android
+ac_add_options --with-android-min-sdk=21
+ac_add_options --target=x86_64-linux-android
+
+ac_add_options --with-branding=mobile/android/branding/nightly
+
+export AR="$topsrcdir/clang/bin/llvm-ar"
+export NM="$topsrcdir/clang/bin/llvm-nm"
+export RANLIB="$topsrcdir/clang/bin/llvm-ranlib"
+
+# Enable LTO if the NDK is available.
+if [ -z "$NO_NDK" ]; then
+  ac_add_options --enable-lto
+fi
+
+export MOZILLA_OFFICIAL=1
+export MOZ_TELEMETRY_REPORTING=1
+export MOZ_ANDROID_POCKET=1
+
+. "$topsrcdir/mobile/android/config/mozconfigs/common.override"

new file mode 100644
--- /dev/null
+++ b/mobile/android/config/mozconfigs/android-x86_64/nightly-artifact
@@ -0,0 +1,12 @@
+. "$topsrcdir/build/mozconfig.artifact.automation"
+
+NO_CACHE=1
+NO_NDK=1
+
+. "$topsrcdir/mobile/android/config/mozconfigs/common"
+
+. "$topsrcdir/mobile/android/config/mozconfigs/android-x86_64/nightly"
+
+. "$topsrcdir/build/mozconfig.artifact"
+
+. "$topsrcdir/mobile/android/config/mozconfigs/common.override"

new file mode 100644
--- /dev/null
+++ b/testing/mozharness/configs/builds/releng_sub_android_configs/64_x86_64.py
@@ -0,0 +1,7 @@
+config = {
+    'base_name': 'Android x86-64 API 21+ %(branch)s',
+    'stage_platform': 'android-x86_64',
+    'src_mozconfig': 'mobile/android/config/mozconfigs/android-x86_64/nightly',
+    'multi_locale_config_platform': 'android',
+    'artifact_flag_build_variant_in_try': 'x86_64-artifact',
+}

new file mode 100644
--- /dev/null
+++ b/testing/mozharness/configs/builds/releng_sub_android_configs/64_x86_64_artifact.py
@@ -0,0 +1,6 @@
+config = {
+    'base_name': 'Android 5.0 x86-64 %(branch)s Artifact build',
+    'stage_platform': 'android-x86_64',
+    'src_mozconfig': 'mobile/android/config/mozconfigs/android-x86_64/nightly-artifact',
+    'tooltool_manifest_src': 'mobile/android/config/tooltool-manifests/android-x86/releng.manifest',
+}

--- a/testing/mozharness/mozharness/mozilla/building/buildbase.py
+++ b/testing/mozharness/mozharness/mozilla/building/buildbase.py
@@ -430,16 +430,18 @@ class BuildOptionParser(object):
         'api-16-gradle': 'builds/releng_sub_%s_configs/%s_api_16_gradle.py',
         'api-16-gradle-artifact': 'builds/releng_sub_%s_configs/%s_api_16_gradle_artifact.py',
         'api-16-without-google-play-services': 'builds/releng_sub_%s_configs/%s_api_16_without_google_play_services.py',
         'rusttests': 'builds/releng_sub_%s_configs/%s_rusttests.py',
         'rusttests-debug': 'builds/releng_sub_%s_configs/%s_rusttests_debug.py',
         'x86': 'builds/releng_sub_%s_configs/%s_x86.py',
         'x86-artifact': 'builds/releng_sub_%s_configs/%s_x86_artifact.py',
         'x86-fuzzing-debug': 'builds/releng_sub_%s_configs/%s_x86_fuzzing_debug.py',
+        'x86_64': 'builds/releng_sub_%s_configs/%s_x86_64.py',
+        'x86_64-artifact': 'builds/releng_sub_%s_configs/%s_x86_64_artifact.py',
         'api-16-partner-sample1': 'builds/releng_sub_%s_configs/%s_api_16_partner_sample1.py',
         'aarch64': 'builds/releng_sub_%s_configs/%s_aarch64.py',
         'android-test': 'builds/releng_sub_%s_configs/%s_test.py',
         'android-test-ccov': 'builds/releng_sub_%s_configs/%s_test_ccov.py',
         'android-checkstyle': 'builds/releng_sub_%s_configs/%s_checkstyle.py',
         'android-lint': 'builds/releng_sub_%s_configs/%s_lint.py',
         'android-findbugs': 'builds/releng_sub_%s_configs/%s_findbugs.py',
         'android-geckoview-docs': 'builds/releng_sub_%s_configs/%s_geckoview_docs.py',