diff --git a/src/Customer/Listeners/ClaimGuestOrdersOnLogin.php b/src/Customer/Listeners/ClaimGuestOrdersOnLogin.php
new file mode 100644
index 0000000..f1172b8
--- /dev/null
+++ b/src/Customer/Listeners/ClaimGuestOrdersOnLogin.php
@@ -0,0 +1,24 @@
+<?php
+
+namespace Modules\Core\Customer\Listeners;
+
+use Modules\Core\Auth\Events\UserAuthenticated;
+use Modules\Core\Customer\Services\GuestOrderClaimer;
+
+/**
+ * Registered from Providers\CustomerServiceProvider — UserAuthenticated
+ * only fires after a valid login code, which is what makes matching
+ * placed guest orders by email safe (see GuestOrderClaimer's own
+ * docblock).
+ */
+class ClaimGuestOrdersOnLogin
+{
+    public function __construct(
+        private readonly GuestOrderClaimer $claimer,
+    ) {}
+
+    public function handle(UserAuthenticated $event): void
+    {
+        $this->claimer->claim($event->user);
+    }
+}
diff --git a/src/Customer/Services/GuestOrderClaimer.php b/src/Customer/Services/GuestOrderClaimer.php
new file mode 100644
index 0000000..3ca626c
--- /dev/null
+++ b/src/Customer/Services/GuestOrderClaimer.php
@@ -0,0 +1,41 @@
+<?php
+
+namespace Modules\Core\Customer\Services;
+
+use Illuminate\Contracts\Auth\Authenticatable;
+use Lunar\Base\LunarUser;
+use Lunar\Models\Order;
+
+/**
+ * Attaches placed guest orders to an account when their billing email
+ * matches the account's email, case-insensitively. Only ever called right
+ * after the shopper has proved they own that email — a login code
+ * (Auth\Events\UserAuthenticated), or the code confirming an email change
+ * (a consuming app's own email-change flow, e.g. 3dealer's Account\
+ * EmailController::verify()) — which is what makes matching on email safe.
+ *
+ * Only orders with no customer_id AND no user_id are touched: an order
+ * already attached to any account (guest or otherwise) is left alone.
+ */
+class GuestOrderClaimer
+{
+    public function claim(Authenticatable&LunarUser $user): int
+    {
+        $customer = $user->latestCustomer();
+
+        if (! $customer || ! $user->email) {
+            return 0;
+        }
+
+        return Order::query()
+            ->whereNotNull('placed_at')
+            ->whereNull('customer_id')
+            ->whereNull('user_id')
+            ->whereHas('billingAddress', fn ($query) => $query
+                ->whereRaw('lower(contact_email) = ?', [strtolower($user->email)]))
+            ->update([
+                'customer_id' => $customer->id,
+                'user_id' => $user->id,
+            ]);
+    }
+}
diff --git a/src/Providers/CustomerServiceProvider.php b/src/Providers/CustomerServiceProvider.php
index 9d0cde3..96940c1 100644
--- a/src/Providers/CustomerServiceProvider.php
+++ b/src/Providers/CustomerServiceProvider.php
@@ -6,11 +6,13 @@ use Illuminate\Support\Facades\Event;
 use Illuminate\Support\ServiceProvider;
 use Lunar\Facades\ModelManifest;
 use Lunar\Models\Contracts\Customer as LunarCustomer;
+use Modules\Core\Auth\Events\UserAuthenticated;
 use Modules\Core\Auth\Events\UserCreated;
 use Modules\Core\Customer\Events\CustomerAddressCreated;
 use Modules\Core\Customer\Events\CustomerAddressDeleted;
 use Modules\Core\Customer\Events\CustomerAddressUpdated;
 use Modules\Core\Customer\Events\CustomerProfileUpdated;
+use Modules\Core\Customer\Listeners\ClaimGuestOrdersOnLogin;
 use Modules\Core\Customer\Listeners\CreateCustomerForUser;
 use Modules\Core\Customer\Listeners\LogCustomerAccountActivity;
 use Modules\Core\Customer\Models\Customer;
@@ -35,6 +37,7 @@ class CustomerServiceProvider extends ServiceProvider
         $this->app->booted(fn () => ModelManifest::replace(LunarCustomer::class, Customer::class));
 
         Event::listen(UserCreated::class, CreateCustomerForUser::class);
+        Event::listen(UserAuthenticated::class, ClaimGuestOrdersOnLogin::class);
 
         Event::listen(CustomerAddressCreated::class, [LogCustomerAccountActivity::class, 'handleAddressCreated']);
         Event::listen(CustomerAddressUpdated::class, [LogCustomerAccountActivity::class, 'handleAddressUpdated']);