diff --git a/src/inc/sift-object-validator.php b/src/inc/sift-object-validator.php
index f1b6cfb..5f60211 100644
--- a/src/inc/sift-object-validator.php
+++ b/src/inc/sift-object-validator.php
@@ -686,6 +686,21 @@ class SiftObjectValidator {
 		'$other',
 	);
 
+	const ORDER_STATUSES = array(
+		'$approved',
+		'$canceled',
+		'$held',
+		'$fulfilled',
+		'$returned',
+	);
+
+	const CANCELLATION_REASONS = array(
+		'$payment_risk',
+		'$abuse',
+		'$policy',
+		'$other',
+	);
+
 	/**
 	 * This is the main validation function.
 	 *
@@ -1523,4 +1538,48 @@ public static function validate_update_password( $data ) {
 		}
 		return true;
 	}
+
+	/**
+	 * Validate the order status event.
+	 *
+	 * @param array $data The event to validate.
+	 *
+	 * @return true
+	 * @throws \Exception If the event is invalid.
+	 */
+	public static function validate_order_status( array $data ) {
+		$validator_map = array(
+			'$user_id'      => array( __CLASS__, 'validate_id' ),
+			'$order_id'     => 'is_string',
+			'$order_status' => self::ORDER_STATUSES,
+			'$reason'       => self::CANCELLATION_REASONS,
+			'$source'       => array( '$automated', '$manual_review' ),
+			'$analyst'      => 'is_string',
+			'$webhook_id'   => 'is_string',
+			'$description'  => 'is_string',
+			'$browser'      => array( __CLASS__, 'validate_browser' ),
+			'$app'          => array( __CLASS__, 'validate_app' ),
+			'$brand_name'   => 'is_string',
+			'$site_country' => array( __CLASS__, 'validate_country_code' ),
+			'$site_domain'  => 'is_string',
+		);
+
+		try {
+			static::validate( $data, $validator_map );
+			// Required fields for order status: $user_id, $order_id, $order_status
+			if ( empty( $data['$user_id'] ) ) {
+				throw new \Exception( 'missing $user_id' );
+			}
+			if ( empty( $data['$order_id'] ) ) {
+				throw new \Exception( 'missing $order_id' );
+			}
+			if ( empty( $data['$order_status'] ) ) {
+				throw new \Exception( 'missing $order_status' );
+			}
+		} catch ( \Exception $e ) {
+			throw new \Exception( 'Invalid $order_status event: ' . esc_html( $e->getMessage() ) );
+		}
+
+		return true;
+	}
 }
diff --git a/src/inc/woocommerce-actions.php b/src/inc/woocommerce-actions.php
index 0a89d1b..6113e4e 100644
--- a/src/inc/woocommerce-actions.php
+++ b/src/inc/woocommerce-actions.php
@@ -13,6 +13,16 @@
 class Events {
 	public static $to_send = array();
 
+	const SUPPORTED_STATUS_CHANGES = array(
+		'pending',
+		'processing',
+		'on-hold',
+		'completed',
+		'cancelled',
+		'refunded',
+		'failed',
+	);
+
 	/**
 	 * Set up the integration hooks for messages we want to send to Sift.
 	 *
@@ -30,9 +40,20 @@ public static function hooks() {
 
 		add_action( 'woocommerce_checkout_order_processed', array( static::class, 'create_order' ), 100, 3 );
 		add_action( 'woocommerce_new_order', array( static::class, 'add_session_info' ), 100 );
-		add_action( 'woocommerce_order_status_changed', array( static::class, 'change_order_status' ), 100 );
 		add_action( 'post_updated', array( static::class, 'update_order' ), 100 );
 
+		/**
+		 * We need to break this out into separate actions so we have the $status_transition available.
+		 *
+		 * This limits the number of supported status transitions so if we have an unsupported transition we need to
+		 * log it.
+		 */
+		foreach ( self::SUPPORTED_STATUS_CHANGES as $status ) {
+			add_action( 'woocommerce_order_status_' . $status, array( static::class, 'change_order_status' ), 100, 3 );
+		}
+		// For unsupported actions.
+		add_action( 'woocommerce_order_status_changed', array( static::class, 'maybe_log_change_order_status' ), 100, 3 );
+
 		/**
 		 * This action merged in to WooCommerce and shipped via 8.8.0
 		 * https://github.com/woocommerce/woocommerce/pull/45146
@@ -512,16 +533,89 @@ public static function create_order( string $order_id, array $posted_data, \WC_O
 	 */
 	public static function add_session_info( string $order_id ) {}
 
+	/**
+	 * Log error for unsupported status changes.
+	 *
+	 * @param string $order_id Order ID.
+	 * @param string $from     From status.
+	 * @param string $to       To status.
+	 *
+	 * @return void
+	 */
+	public static function maybe_log_change_order_status( string $order_id, string $from, string $to ) {
+		if ( ! in_array( $to, self::SUPPORTED_STATUS_CHANGES, true ) ) {
+			wc_get_logger()->error(
+				sprintf(
+					'Unsupported status change from %s to %s for order %s.',
+					$from,
+					$to,
+					$order_id
+				)
+			);
+		}
+	}
+
 	/**
 	 * Adds the event for the order status update
 	 *
 	 * @link https://developers.sift.com/docs/curl/events-api/reserved-events/order-status
 	 *
-	 * @param string $order_id Order ID.
+	 * @param string    $order_id          Order ID.
+	 * @param \WC_Order $order             The order object.
+	 * @param array     $status_transition Status transition data.
+	 *                                     type: array<string $from, string $to, string $note, boolean $manual>.
 	 *
 	 * @return void
 	 */
-	public static function change_order_status( string $order_id ) {}
+	public static function change_order_status( string $order_id, \WC_Order $order, array $status_transition ) {
+		if ( ! in_array( $status_transition['to'], self::SUPPORTED_STATUS_CHANGES, true ) ) {
+			self::maybe_log_change_order_status( $order_id, $status_transition['from'], $status_transition['to'] );
+			return;
+		}
+
+		$properties = array(
+			'$user_id'      => (string) $order->get_user_id(),
+			'$order_id'     => (string) $order_id,
+			'$source'       => $status_transition['manual'] ? '$manual_review' : '$automated',
+			'$description'  => $status_transition['note'],
+			'$browser'      => self::get_client_browser(),
+			'$site_country' => wc_get_base_location()['country'],
+			'$site_domain'  => wp_parse_url( site_url(), PHP_URL_HOST ),
+			'$ip'           => self::get_client_ip(),
+			'$time'         => intval( 1000 * microtime( true ) ),
+		);
+
+		// Add the $order_status property (based on the status transition).
+		switch ( $status_transition['to'] ) {
+			case 'pending':
+			case 'processing':
+			case 'on-hold':
+				$properties['$order_status'] = '$held';
+				break;
+			case 'completed':
+				$properties['$order_status'] = '$fulfilled';
+				break;
+			case 'cancelled':
+			case 'refunded':
+			case 'failed':
+				$properties['$order_status'] = '$canceled';
+				break;
+		}
+
+		// For manual reviews add the user as the `$analyst`.
+		if ( $status_transition['manual'] ?? false ) {
+			$properties['$analyst'] = wp_get_current_user()->user_login;
+		}
+
+		try {
+			SiftObjectValidator::validate_order_status( $properties );
+		} catch ( \Exception $e ) {
+			wc_get_logger()->error( esc_html( $e->getMessage() ) );
+			return;
+		}
+
+		self::add( '$order_status', $properties );
+	}
 
 	/**
 	 * Adds event for order update
diff --git a/tests/EventTest.php b/tests/EventTest.php
index d9eefba..dbbb671 100644
--- a/tests/EventTest.php
+++ b/tests/EventTest.php
@@ -89,7 +89,7 @@ private static function create_simple_product() {
 	 *
 	 * @return array
 	 */
-	private static function array_dot( mixed $multidimensional_array ) {
+	protected static function array_dot( mixed $multidimensional_array ) {
 		$flat = [];
 		$it   = new RecursiveIteratorIterator( new RecursiveArrayIterator( $multidimensional_array ) );
 		foreach ( $it as $leaf ) {
diff --git a/tests/OrderStatusEventTest.php b/tests/OrderStatusEventTest.php
new file mode 100644
index 0000000..26b749f
--- /dev/null
+++ b/tests/OrderStatusEventTest.php
@@ -0,0 +1,86 @@
+<?php
+/**
+ * Class OrderStatusEventTest
+ *
+ * @package Sift_Decisions
+ */
+
+require_once 'EventTest.php';
+
+// phpcs:disable Universal.Arrays.DisallowShortArraySyntax.Found, WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedClassFound
+
+use WPCOMSpecialProjects\SiftDecisions\WooCommerce_Actions\Events;
+
+/**
+ * Test case.
+ */
+class OrderStatusEventTest extends EventTest {
+	/**
+	 * Test that the $create_order event is triggered.
+	 *
+	 * @return void
+	 */
+	public function test_change_order_status() {
+		// Arrange
+		// - create a user and log them in
+		$user_id = $this->factory()->user->create();
+		wp_set_current_user( $user_id );
+
+		$_REQUEST['woocommerce-process-checkout-nonce'] = wp_create_nonce( 'woocommerce-process_checkout' );
+		add_filter( 'woocommerce_checkout_fields', fn() => [], 10, 0 );
+		add_filter( 'woocommerce_cart_needs_payment', '__return_false' );
+
+		// Act
+		WC()->cart->add_to_cart( static::$product_id );
+		$co = WC_Checkout::instance();
+		$co->process_checkout();
+
+		// Assert
+		static::fail_on_error_logged();
+		$events = static::assertOrderStatusEventTriggered(
+			[
+				'$source'       => '$automated',
+				'$order_status' => '$held',
+			]
+		);
+
+		// Let's manually change the status of the order by cancelling it.
+		$order_id = $events[0]['properties.$order_id'];
+		$order    = wc_get_order( $order_id );
+		$order->update_status( 'cancelled', '', true );
+		static::fail_on_error_logged();
+		static::assertOrderStatusEventTriggered(
+			[
+				'$source'       => '$manual_review',
+				'$order_status' => '$canceled',
+			]
+		);
+
+		// Let's try an unsupported status.
+		$gold_status_filter = fn( $statuses ) => array_merge( $statuses, [ 'wc-gold' => 'Gold' ] );
+		add_filter( 'wc_order_statuses', $gold_status_filter );
+		$order->update_status( 'gold', '', true );
+		static::assertNotEmpty( static::$errors, 'No error logged for unsupported status' );
+
+		// Clean up
+		remove_filter( 'wc_order_statuses', $gold_status_filter );
+		wp_delete_user( $user_id );
+	}
+
+	/**
+	 * Assert $order_status event is triggered.
+	 *
+	 * @param array $props Event properties.
+	 *
+	 * @return array Return the matching events.
+	 */
+	public static function assertOrderStatusEventTriggered( array $props = [] ) {
+		$filters = [ 'event' => '$order_status' ];
+		if ( ! empty( $props ) ) {
+			$filters = array_merge( $filters, static::array_dot( [ 'properties' => $props ] ) );
+		}
+		$events = static::filter_events( $filters );
+		static::assertGreaterThanOrEqual( 1, count( $events ), 'No $order_status event found' );
+		return $events;
+	}
+}
diff --git a/tests/SiftApi/Validate_OrderStatus_Test.php b/tests/SiftApi/Validate_OrderStatus_Test.php
new file mode 100644
index 0000000..66e937d
--- /dev/null
+++ b/tests/SiftApi/Validate_OrderStatus_Test.php
@@ -0,0 +1,57 @@
+<?php declare( strict_types = 1 );
+
+// phpcs:disable
+
+namespace SiftApi;
+
+use WPCOMSpecialProjects\SiftDecisions\Sift\SiftObjectValidator;
+
+if ( ! defined( 'ABSPATH' ) ) {
+	exit;
+}
+
+require_once 'SiftObjectValidatorTest.php';
+
+class Validate_OrderStatus_Test extends SiftObjectValidatorTest {
+	protected static ?string $fixture_name = 'order-status.json';
+
+	protected static function validator( $data ) {
+		return SiftObjectValidator::validate_order_status( $data );
+	}
+
+	public function test_user_id_required() {
+		static::assert_invalid_argument_exception(
+			static::modify_data( [ '$user_id' => null ] ),
+			'missing $user_id'
+		);
+	}
+
+	public function test_order_id_required() {
+		static::assert_invalid_argument_exception(
+			static::modify_data( [ '$order_id' => null ] ),
+			'missing $order_id'
+		);
+	}
+
+	public function test_order_status_required() {
+		static::assert_invalid_argument_exception(
+			static::modify_data( [ '$order_status' => null ] ),
+			'missing $order_status'
+		);
+	}
+
+	public function test_app_browser_set() {
+		$data = static::load_json();
+		static::assert_invalid_argument_exception(
+			$data,
+			'Cannot have both $app and $browser'
+		);
+	}
+
+	public function test_site_country() {
+		static::assert_invalid_argument_exception(
+			static::modify_data( [ '$site_country' => 'US1' ] ),
+			'$site_country: must be an ISO 3166 country code'
+		);
+	}
+}
diff --git a/tests/SiftApi/fixtures/order-status.json b/tests/SiftApi/fixtures/order-status.json
new file mode 100644
index 0000000..a4aecc8
--- /dev/null
+++ b/tests/SiftApi/fixtures/order-status.json
@@ -0,0 +1,31 @@
+{
+	"$user_id"          : "billy_jones_301",
+	"$order_id"         : "ORDER-28168441",
+	"$order_status"     : "$canceled",
+
+	"$reason"           : "$payment_risk",
+	"$source"           : "$manual_review",
+	"$analyst"          : "someone@your-site.com",
+	"$webhook_id"       : "3ff1082a4aea8d0c58e3643ddb7a5bb87ffffeb2492dca33",
+	"$description"      : "Canceling because multiple fraudulent users on device",
+	"$ip"               : "54.208.214.78",
+
+
+	"$browser"        : {
+		"$user_agent"       : "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36",
+		"$accept_language"  : "en-US",
+		"$content_language" : "en-GB"
+	},
+
+	"$app"        : {
+
+		"$os"                  : "iOS",
+		"$os_version"          : "10.1.3",
+		"$device_manufacturer" : "Apple",
+		"$device_model"        : "iPhone 4,2",
+		"$device_unique_id"    : "A3D261E4-DE0A-470B-9E4A-720F3D3D22E6",
+		"$app_name"            : "Calculator",
+		"$app_version"         : "3.2.7",
+		"$client_language"     : "en-US"
+	}
+}