diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3a67f03..b2042e9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -41,11 +41,17 @@ jobs:
         run: cargo test --locked
 
   integration-test:
-    runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
-        builder: ["builder:22", "builder:20"]
+        builder: ["builder:24", "builder:22", "builder:20"]
+        arch: ["amd64", "arm64"]
+        exclude:
+          - builder: "builder:22"
+            arch: "arm64"
+          - builder: "builder:20"
+            arch: "arm64"
+    runs-on: ${{ matrix.arch == 'arm64' && 'pub-hk-ubuntu-22.04-arm-medium' || 'ubuntu-latest' }}
     env:
       INTEGRATION_TEST_CNB_BUILDER: heroku/${{ matrix.builder }}
     steps:
@@ -54,11 +60,11 @@ jobs:
         with:
           submodules: true
       - name: Install musl-tools
-        run: sudo apt-get install musl-tools --no-install-recommends
+        run: sudo apt-get install -y --no-install-recommends musl-tools
       - name: Update Rust toolchain
         run: rustup update
       - name: Install Rust linux-musl target
-        run: rustup target add x86_64-unknown-linux-musl
+        run: rustup target add ${{ matrix.arch == 'arm64' && 'aarch64' || 'x86_64' }}-unknown-linux-musl
       - name: Rust Cache
         uses: Swatinem/rust-cache@v2.7.3
       - name: Install Pack CLI
@@ -69,4 +75,4 @@ jobs:
       # only those and not the unit tests, via the `--ignored` option. On the latest stack
       # we run all integration tests, but on older stacks we only run stack-specific tests.
       - name: Run integration tests (all tests)
-        run: cargo test --locked -- --ignored --test-threads 5
+        run: cargo test --locked -- --ignored --test-threads $(($(nproc)+1))
diff --git a/buildpacks/php/CHANGELOG.md b/buildpacks/php/CHANGELOG.md
index d2a47e5..07adc27 100644
--- a/buildpacks/php/CHANGELOG.md
+++ b/buildpacks/php/CHANGELOG.md
@@ -10,6 +10,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - Add PHP/8.3, update PHP runtimes, extensions, Composers, web servers (#104)
+- Support Ubuntu 24.04 (and, as a result, Heroku-24 and `heroku/builder:24`)
+- Support `arm64` CPU architecture (Ubuntu 24.04 / Heroku-24 only)
 
 ### Changed
 
diff --git a/buildpacks/php/buildpack.toml b/buildpacks/php/buildpack.toml
index 4407e6b..2f68cd9 100644
--- a/buildpacks/php/buildpack.toml
+++ b/buildpacks/php/buildpack.toml
@@ -23,5 +23,17 @@ version = "20.04"
 name = "ubuntu"
 version = "22.04"
 
+[[targets.distros]]
+name = "ubuntu"
+version = "24.04"
+
+[[targets]]
+os = "linux"
+arch = "arm64"
+
+[[targets.distros]]
+name = "ubuntu"
+version = "24.04"
+
 [metadata.release]
 image = { repository = "docker.io/heroku/buildpack-php" }
diff --git a/buildpacks/php/src/platform.rs b/buildpacks/php/src/platform.rs
index accda31..d3daef5 100644
--- a/buildpacks/php/src/platform.rs
+++ b/buildpacks/php/src/platform.rs
@@ -41,7 +41,7 @@ pub(crate) fn heroku_stack_name_for_target(target: &Target) -> Result<String, St
         ..
     } = target;
     match (os.as_str(), distro_name.as_str(), distro_version.as_str()) {
-        ("linux", "ubuntu", v @ ("20.04" | "22.04")) => {
+        ("linux", "ubuntu", v @ ("20.04" | "22.04" | "24.04")) => {
             Ok(format!("heroku-{}", v.strip_suffix(".04").unwrap_or(v)))
         }
         _ => Err(format!("{os}-{distro_name}-{distro_version}")),
diff --git a/buildpacks/php/tests/integration/utils.rs b/buildpacks/php/tests/integration/utils.rs
index b9a32cf..2616aef 100644
--- a/buildpacks/php/tests/integration/utils.rs
+++ b/buildpacks/php/tests/integration/utils.rs
@@ -73,10 +73,18 @@ pub(crate) fn smoke_test<P, B>(
     P: AsRef<Path>,
     B: Into<Vec<BuildpackReference>>,
 {
-    let build_config = BuildConfig::new(builder_name.as_ref(), app_dir)
+    let mut build_config = BuildConfig::new(builder_name.as_ref(), app_dir)
         .buildpacks(buildpacks.into())
         .clone();
 
+    let target_triple = match builder_name.as_ref() {
+        // Compile the buildpack for ARM64 iff the builder supports multi-arch and the host is ARM64.
+        "heroku/builder:24" if cfg!(target_arch = "aarch64") => "aarch64-unknown-linux-musl",
+        _ => "x86_64-unknown-linux-musl",
+    };
+
+    build_config.target_triple(target_triple);
+
     TestRunner::default().build(&build_config, |context| {
         start_container_assert_basic_http_response(&context, expected_http_response_body_contains);
 
@@ -89,7 +97,7 @@ pub(crate) fn smoke_test<P, B>(
     });
 }
 
-const DEFAULT_INTEGRATION_TEST_BUILDER: &str = "heroku/builder:22";
+const DEFAULT_INTEGRATION_TEST_BUILDER: &str = "heroku/builder:24";
 
 const UREQ_RESPONSE_RESULT_EXPECT_MESSAGE: &str = "http request should be successful";