diff --git a/ci/src/build-handler/index.mjs b/ci/src/build-handler/index.mjs
index be73a4222..a0aa0186c 100644
--- a/ci/src/build-handler/index.mjs
+++ b/ci/src/build-handler/index.mjs
@@ -67,6 +67,40 @@ function eventIsPullRequest(event) {
   return false;
 }
 
+/**
+ *
+ * @param {GitHubPullRequestWebhookPayload|GitHubPushWebhookPayload} event
+ * @param {string} buildspec
+ * @param {object} environmentVariables
+ * @param {string} projectName
+ * @param {object} extraEnvironmentVariables
+ */
+async function startBuild(
+  event,
+  buildspec,
+  environmentVariables,
+  projectName,
+  extraEnvironmentVariables,
+) {
+  const environmentVariablesOverride = {
+    ...environmentVariables,
+    ...extraEnvironmentVariables,
+  };
+
+  return codebuild.send(
+    new StartBuildCommand({
+      projectName,
+      sourceTypeOverride: 'GITHUB',
+      sourceLocationOverride: event.repository.clone_url,
+      sourceVersion: eventIsPullRequest(event)
+        ? `pr/${event.pull_request.number}`
+        : event.after,
+      buildspecOverride: buildspec,
+      environmentVariablesOverride,
+    }),
+  );
+}
+
 /**
  * `startBuild` returns a Build object
  * https://docs.aws.amazon.com/codebuild/latest/APIReference/API_Build.html
@@ -147,18 +181,40 @@ async function triggerBuild(ciContentsResponse, event) {
     environmentVariables.push({ name: 'PRX_GITHUB_AFTER', value: after });
   }
 
-  await codebuild.send(
-    new StartBuildCommand({
-      projectName: process.env.CODEBUILD_PROJECT_NAME,
-      sourceTypeOverride: 'GITHUB',
-      sourceLocationOverride: event.repository.clone_url,
-      sourceVersion: eventIsPullRequest(event)
-        ? `pr/${event.pull_request.number}`
-        : event.after,
-      buildspecOverride: buildspec,
-      environmentVariablesOverride: environmentVariables,
-    }),
-  );
+  // If the buildspec explicitly specifies any architectures, only include the
+  // architectures listed
+  if (
+    buildspec.includes('PRX_BUILD_X86_64') ||
+    buildspec.includes('PRX_BUILD_AARCH64')
+  ) {
+    if (buildspec.includes('PRX_BUILD_X86_64')) {
+      await startBuild(
+        event,
+        buildspec,
+        environmentVariables,
+        process.env.X64_CODEBUILD_PROJECT_NAME,
+        { name: 'PRX_TARGET_ARCHITECTURE', value: 'x86_64' },
+      );
+    }
+
+    if (buildspec.includes('PRX_BUILD_AARCH64')) {
+      await startBuild(
+        event,
+        buildspec,
+        environmentVariables,
+        process.env.ARM_CODEBUILD_PROJECT_NAME,
+        { name: 'PRX_TARGET_ARCHITECTURE', value: 'aarch64' },
+      );
+    }
+  } else {
+    await startBuild(
+      event,
+      buildspec,
+      environmentVariables,
+      process.env.X64_CODEBUILD_PROJECT_NAME,
+      { name: 'PRX_TARGET_ARCHITECTURE', value: 'x86_64' },
+    );
+  }
 
   console.log('CodeBuild started');
 }
diff --git a/ci/template.yml b/ci/template.yml
index 328e36b57..1244c78e4 100644
--- a/ci/template.yml
+++ b/ci/template.yml
@@ -290,7 +290,8 @@ Resources:
       Environment:
         Variables:
           GITHUB_ACCESS_TOKEN: !Ref GitHubToken
-          CODEBUILD_PROJECT_NAME: !Ref CiCodeBuildProject
+          X64_CODEBUILD_PROJECT_NAME: !Ref CiCodeBuildProject
+          ARM_CODEBUILD_PROJECT_NAME: !Ref CiCodeBuildArmProject
           AWS_ACCOUNT_ID: !Ref AWS::AccountId
       Events:
         GitHubWebhook:
diff --git a/ci/utility/post_build.sh b/ci/utility/post_build.sh
index 3d342ee93..3d370d1a5 100755
--- a/ci/utility/post_build.sh
+++ b/ci/utility/post_build.sh
@@ -41,18 +41,20 @@ push_to_ecr() {
             fi
             set -e
 
+            arch="${PRX_TARGET_ARCHITECTURE}"
+
             # e.g., github/prx/porter
             image_name="${safe_ecr_repo_name}"
 
             # e.g., 123456789012.dkr.ecr.us-east-1.amazonaws.com
             ecr_domain="${PRX_AWS_ACCOUNT_ID}.dkr.ecr.${AWS_DEFAULT_REGION}.amazonaws.com"
 
-            # This is always just the Git commit hash
-            # e.g., de67a8d77768093b20a9ae961a78313a3c0ef096
-            commit_image_tag="${PRX_COMMIT}"
-            # e.g., github/prx/porter:de67a8d77768093b20a9ae961a78313a3c0ef096
+            # This is the Git commit hash with the architecture
+            # e.g., de67a8d77768093b20a9ae961a78313a3c0ef096-aarch64
+            commit_image_tag="${PRX_COMMIT}-${arch}"
+            # e.g., github/prx/porter:de67a8d77768093b20a9ae961a78313a3c0ef096-aarch64
             commit_tagged_image_name="${image_name}:${commit_image_tag}"
-            # 123456789012.dkr.ecr.us-east-1.amazonaws.com/github/prx/porter:de67a8d77768093b20a9ae961a78313a3c0ef096
+            # 123456789012.dkr.ecr.us-east-1.amazonaws.com/github/prx/porter:de67a8d77768093b20a9ae961a78313a3c0ef096-aarch64
             commit_full_image_uri="${ecr_domain}/${commit_tagged_image_name}"
 
             # PRX_CI_PUBLISH is the indicator that production artifacts should
@@ -65,16 +67,16 @@ push_to_ecr() {
             # tag should include a `prerelease-` prefix.
             if [ "$PRX_CI_PUBLISH" = "true" ]
             then
-                # e.g., release-de67a8d77768093b20a9ae961a78313a3c0ef096
-                prefix_image_tag="release-${PRX_COMMIT}"
+                # e.g., release-de67a8d77768093b20a9ae961a78313a3c0ef096-aarch64
+                prefix_image_tag="release-${PRX_COMMIT}-${arch}"
             else
-                # e.g., prerelease-de67a8d77768093b20a9ae961a78313a3c0ef096
-                prefix_image_tag="prerelease-${PRX_COMMIT}"
+                # e.g., prerelease-de67a8d77768093b20a9ae961a78313a3c0ef096-aarch64
+                prefix_image_tag="prerelease-${PRX_COMMIT}-${arch}"
             fi
 
-            # e.g., github/prx/porter:release-de67a8d77768093b20a9ae961a78313a3c0ef096
+            # e.g., github/prx/porter:release-de67a8d77768093b20a9ae961a78313a3c0ef096-aarch64
             prefix_tagged_image_name="${image_name}:${prefix_image_tag}"
-            # 123456789012.dkr.ecr.us-east-1.amazonaws.com/github/prx/porter:release-de67a8d77768093b20a9ae961a78313a3c0ef096
+            # 123456789012.dkr.ecr.us-east-1.amazonaws.com/github/prx/porter:release-de67a8d77768093b20a9ae961a78313a3c0ef096-aarch64
             prefix_full_image_uri="${ecr_domain}/${prefix_tagged_image_name}"
 
             # Export a variable whose name is the LABEL from the Dockerfile,
@@ -83,6 +85,10 @@ push_to_ecr() {
             # this would set WEB_SERVER=1234.dkr.ecr.us-eas-1.amazonaws.com...
             declare -gx "$label"="$commit_tagged_image_name"
 
+            # The image is tagged and pushed twice, which results in one image
+            # in ECR with both tags. The "commit" tag is what is used in
+            # Parameter Store, ECS tasks, etc, but the "prefix" tag is added
+            # so that ECR lifecycle rules can handle releases properly.
             echo "> Pushing image $image_id to ECR $commit_full_image_uri"
             docker tag $image_id $commit_full_image_uri
             docker push $commit_full_image_uri