diff --git a/src/Cart.php b/src/Cart.php
index f84a5a9..73019ce 100644
--- a/src/Cart.php
+++ b/src/Cart.php
@@ -5,7 +5,10 @@
 namespace Wearepixel\Cart;
 
 use Closure;
+use Wearepixel\Cart\Coupons\Coupon;
 use Wearepixel\Cart\Helpers\Helpers;
+use Wearepixel\Cart\Shipping\ShippingRate;
+use Wearepixel\Cart\Tax\TaxRule;
 use Wearepixel\Cart\Validators\CartItemValidator;
 use Wearepixel\Cart\Exceptions\InvalidItemException;
 use Wearepixel\Cart\Exceptions\UnknownModelException;
@@ -276,6 +279,21 @@ public function condition(array|CartCondition $condition): self
         return $this;
     }
 
+    public function coupon(Coupon $coupon): self
+    {
+        return $this->condition($coupon->toCondition());
+    }
+
+    public function tax(TaxRule $taxRule): self
+    {
+        return $this->condition($taxRule->toCondition());
+    }
+
+    public function shipping(ShippingRate $shippingRate): self
+    {
+        return $this->condition($shippingRate->toCondition());
+    }
+
     public function getConditions(bool $array = false, bool $active = false): CartConditionCollection|array
     {
         $conditions = new CartConditionCollection($this->driver->getConditions());
diff --git a/tests/Unit/CartFirstClassObjectsTest.php b/tests/Unit/CartFirstClassObjectsTest.php
new file mode 100644
index 0000000..650959b
--- /dev/null
+++ b/tests/Unit/CartFirstClassObjectsTest.php
@@ -0,0 +1,100 @@
+<?php
+
+declare(strict_types=1);
+
+use Wearepixel\Cart\Cart;
+use Wearepixel\Cart\CartCondition;
+use Wearepixel\Cart\Coupons\Coupon;
+use Wearepixel\Cart\Drivers\SessionDriver;
+use Wearepixel\Cart\Exceptions\InvalidCouponException;
+use Wearepixel\Cart\Shipping\ShippingRate;
+use Wearepixel\Cart\Tax\TaxRule;
+use Wearepixel\Cart\Tests\Helpers\SessionMock;
+
+function makeCart(): Cart
+{
+    $events = Mockery::mock('Illuminate\Contracts\Events\Dispatcher');
+    $events->shouldReceive('dispatch');
+
+    return new Cart(
+        new SessionDriver(new SessionMock, 'TESTKEY'),
+        $events,
+        'cart',
+        require __DIR__ . '/../Helpers/ConfigMock.php',
+    );
+}
+
+class TestCoupon extends Coupon
+{
+    protected string $code = 'SAVE10';
+    protected string $value = '-10%';
+    public function isValid(): bool { return true; }
+}
+
+class InvalidTestCoupon extends Coupon
+{
+    protected string $code = 'EXPIRED';
+    protected string $value = '-10%';
+    public function isValid(): bool { return false; }
+}
+
+class TestTax extends TaxRule
+{
+    protected string $name = 'GST';
+    protected string $value = '10%';
+    public function isApplicable(): bool { return true; }
+}
+
+class TestShipping extends ShippingRate
+{
+    protected string $name = 'Flat Rate';
+    protected string $value = '+10';
+    public function isApplicable(): bool { return true; }
+}
+
+beforeEach(function () {
+    $this->cart = makeCart();
+    $this->cart->add(1, 'Widget', 100.00, 1);
+});
+
+afterEach(fn() => Mockery::close());
+
+describe('Cart first-class objects', function () {
+    test('Cart::coupon() applies condition from a Coupon instance', function () {
+        $this->cart->coupon(new TestCoupon);
+
+        expect($this->cart->getCondition('SAVE10'))->toBeInstanceOf(CartCondition::class);
+        expect($this->cart->getSubTotal())->toEqual(90.00);
+    });
+
+    test('Cart::coupon() throws when coupon is invalid', function () {
+        expect(fn() => $this->cart->coupon(new InvalidTestCoupon))
+            ->toThrow(InvalidCouponException::class);
+    });
+
+    test('Cart::tax() applies condition from a TaxRule instance', function () {
+        $this->cart->tax(new TestTax);
+
+        expect($this->cart->getCondition('GST'))->toBeInstanceOf(CartCondition::class);
+        expect($this->cart->getSubTotal())->toEqual(110.00);
+    });
+
+    test('Cart::shipping() applies condition from a ShippingRate instance', function () {
+        $this->cart->shipping(new TestShipping);
+
+        expect($this->cart->getCondition('Flat Rate'))->toBeInstanceOf(CartCondition::class);
+        expect($this->cart->getTotal())->toEqual(110.00);
+    });
+
+    test('raw Cart::condition() still works alongside first-class objects', function () {
+        $this->cart->coupon(new TestCoupon);
+        $this->cart->condition(new CartCondition([
+            'name'   => 'Manual Discount',
+            'type'   => 'discount',
+            'value'  => '-5',
+            'target' => 'subtotal',
+        ]));
+
+        expect($this->cart->getConditions()->count())->toBe(2);
+    });
+});