diff --git a/app/code/Magento/QuoteGraphQl/Model/CartItem/Precursor/ConfigurableProductPrecursor.php b/app/code/Magento/QuoteGraphQl/Model/CartItem/Precursor/ConfigurableProductPrecursor.php
new file mode 100644
index 0000000000000..d9eb72e34bc31
--- /dev/null
+++ b/app/code/Magento/QuoteGraphQl/Model/CartItem/Precursor/ConfigurableProductPrecursor.php
@@ -0,0 +1,147 @@
+<?php
+/**
+ * Copyright 2025 Adobe
+ * All Rights Reserved.
+ */
+declare(strict_types=1);
+
+namespace Magento\QuoteGraphQl\Model\CartItem\Precursor;
+
+use Magento\Catalog\Api\Data\ProductInterface;
+use Magento\Catalog\Api\ProductRepositoryInterface;
+use Magento\ConfigurableProduct\Model\Product\Type\Configurable;
+use Magento\Framework\Exception\NoSuchEntityException;
+use Magento\GraphQl\Model\Query\ContextInterface;
+use Magento\QuoteGraphQl\Model\CartItem\PrecursorInterface;
+
+/**
+ * Handles parent-child relationship for configurable products
+ */
+class ConfigurableProductPrecursor implements PrecursorInterface
+{
+    /**
+     * @var array
+     */
+    private array $errors = [];
+
+    /**
+     * @var ProductRepositoryInterface
+     */
+    private ProductRepositoryInterface $productRepository;
+
+    /**
+     * @param ProductRepositoryInterface $productRepository
+     */
+    public function __construct(
+        ProductRepositoryInterface $productRepository
+    ) {
+        $this->productRepository = $productRepository;
+    }
+
+    /**
+     * Process cart item data to handle parent_sku for configurable products
+     *
+     * @param array $cartItemData
+     * @param ContextInterface $_context
+     * @return array
+     */
+    public function process(array $cartItemData, ContextInterface $_context): array
+    {
+        $processedCartItemData = [];
+
+        foreach ($cartItemData as $cartItemIndex => $cartItem) {
+            if (!isset($cartItem['parent_sku'])) {
+                $processedCartItemData[$cartItemIndex] = $cartItem;
+                continue;
+            }
+
+            try {
+                $childProduct = $this->productRepository->get($cartItem['sku']);
+                $parentProduct = $this->productRepository->get($cartItem['parent_sku']);
+
+                if ($parentProduct->getTypeId() !== Configurable::TYPE_CODE) {
+                    $this->errors[] = [
+                        'message' => sprintf('Product %s is not a configurable product', $cartItem['parent_sku']),
+                        'code' => 'UNDEFINED'
+                    ];
+                    $processedCartItemData[$cartItemIndex] = $cartItem;
+                    continue;
+                }
+
+                $configurableOptions = $this->getConfigurableOptions($parentProduct, $childProduct);
+
+                if (empty($configurableOptions)) {
+                    $this->errors[] = [
+                        'message' => sprintf('Could not match child product %s with parent %s',
+                            $cartItem['sku'], $cartItem['parent_sku']),
+                        'code' => 'UNDEFINED'
+                    ];
+                    $processedCartItemData[$cartItemIndex] = $cartItem;
+                    continue;
+                }
+
+                $parentCartItem = [
+                    'sku' => $cartItem['parent_sku'],
+                    'quantity' => $cartItem['quantity'],
+                    'selected_options' => [...$configurableOptions, ...($cartItem['selected_options'] ?? [])],
+                    'entered_options' => $cartItem['entered_options'] ?? [],
+                    'parent_sku' => null
+                ];
+
+                $processedCartItemData[] = $parentCartItem;
+                unset($cartItemData[$cartItemIndex]);
+
+            } catch (NoSuchEntityException $e) {
+                $this->errors[] = [
+                    'message' => $e->getMessage(),
+                    'code' => 'UNDEFINED'
+                ];
+                $processedCartItemData[$cartItemIndex] = $cartItem;
+            }
+        }
+
+        return $processedCartItemData;
+    }
+
+    /**
+     * Get configurable option IDs for the simple product
+     *
+     * @param ProductInterface $parentProduct
+     * @param ProductInterface $childProduct
+     * @return array
+     */
+    private function getConfigurableOptions(ProductInterface $parentProduct, ProductInterface $childProduct): array
+    {
+        $selectedOptions = [];
+
+        /** @var Configurable $configurableType */
+        $configurableType = $parentProduct->getTypeInstance();
+        $attributes = $configurableType->getConfigurableAttributes($parentProduct);
+
+        $childProductData = $childProduct->getData();
+
+        foreach ($attributes as $attribute) {
+            $attributeId = $attribute->getProductAttribute()->getAttributeId();
+            $attributeCode = $attribute->getProductAttribute()->getAttributeCode();
+
+            if (!isset($childProductData[$attributeCode])) {
+                continue;
+            }
+
+            $optionId = $childProductData[$attributeCode];
+            $selectedOptions[] = base64_encode("configurable/$attributeId/$optionId");
+        }
+
+        return $selectedOptions;
+    }
+
+    /**
+     * Return collected errors
+     *
+     * @return array
+     */
+    public function getErrors(): array
+    {
+        return $this->errors;
+    }
+}
diff --git a/app/code/Magento/QuoteGraphQl/Test/Unit/Model/CartItem/Precursor/ConfigurableProductPrecursorTest.php b/app/code/Magento/QuoteGraphQl/Test/Unit/Model/CartItem/Precursor/ConfigurableProductPrecursorTest.php
new file mode 100644
index 0000000000000..9322b4ed66db6
--- /dev/null
+++ b/app/code/Magento/QuoteGraphQl/Test/Unit/Model/CartItem/Precursor/ConfigurableProductPrecursorTest.php
@@ -0,0 +1,265 @@
+<?php
+/**
+ * Copyright 2025 Adobe
+ * All Rights Reserved.
+ */
+declare(strict_types=1);
+
+namespace Magento\QuoteGraphQl\Test\Unit\Model\CartItem\Precursor;
+
+use Magento\Catalog\Api\Data\ProductInterface;
+use Magento\Catalog\Api\ProductRepositoryInterface;
+use Magento\ConfigurableProduct\Model\Product\Type\Configurable;
+use Magento\Eav\Model\Entity\Attribute\AbstractAttribute;
+use Magento\Framework\Exception\NoSuchEntityException;
+use Magento\ConfigurableProduct\Model\Product\Type\Configurable\Attribute;
+use Magento\GraphQl\Model\Query\ContextInterface;
+use Magento\QuoteGraphQl\Model\CartItem\Precursor\ConfigurableProductPrecursor;
+use PHPUnit\Framework\MockObject\Exception;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Unit test for ConfigurableProductPrecursor
+ */
+class ConfigurableProductPrecursorTest extends TestCase
+{
+    /**
+     * @var ConfigurableProductPrecursor
+     */
+    private $precursor;
+
+    /**
+     * @var ProductRepositoryInterface|MockObject
+     */
+    private $productRepositoryMock;
+
+    /**
+     * @var ContextInterface|MockObject
+     */
+    private $contextMock;
+
+    /**
+     * @inheritdoc
+     */
+    protected function setUp(): void
+    {
+        $this->productRepositoryMock = $this->createMock(ProductRepositoryInterface::class);
+        $this->contextMock = $this->createMock(ContextInterface::class);
+        $this->precursor = new ConfigurableProductPrecursor($this->productRepositoryMock);
+    }
+
+    /**
+     * Test processing cart item without parent SKU
+     *
+     * @return void
+     */
+    public function testProcessItemWithoutParentSku(): void
+    {
+        $cartItemData = [
+            [
+                'sku' => 'simple-1',
+                'quantity' => 1,
+                'selected_options' => ['option1'],
+            ]
+        ];
+
+        $result = $this->precursor->process($cartItemData, $this->contextMock);
+
+        $this->assertSame($cartItemData, $result);
+        $this->assertEmpty($this->precursor->getErrors());
+    }
+
+    /**
+     * Test processing valid configurable product
+     *
+     * @return void
+     * @throws Exception
+     */
+    public function testProcessValidConfigurableProduct(): void
+    {
+        $childProduct = $this->getMockProduct('simple-1');
+        $childProduct->method('getData')
+            ->willReturn(['color' => '1']);
+
+        $productAttributeMock = $this->createMock(AbstractAttribute::class);
+        $productAttributeMock->method('getAttributeId')->willReturn('1');
+        $productAttributeMock->method('getAttributeCode')->willReturn('color');
+
+        $attributeMock = $this->getMockBuilder(Attribute::class)
+            ->disableOriginalConstructor()
+            ->addMethods(['getProductAttribute'])
+            ->getMock();
+        $attributeMock->method('getProductAttribute')->willReturn($productAttributeMock);
+
+        $attributesCollection = [$attributeMock];
+
+        $configurableTypeMock = $this->createMock(Configurable::class);
+        $configurableTypeMock->method('getConfigurableAttributes')->willReturn($attributesCollection);
+
+        $parentProduct = $this->getMockProduct('configurable-1', Configurable::TYPE_CODE);
+        $parentProduct->method('getTypeInstance')->willReturn($configurableTypeMock);
+
+        $this->productRepositoryMock->expects($this->exactly(2))
+            ->method('get')
+            ->willReturnMap([
+                ['simple-1', false, null, false, $childProduct],
+                ['configurable-1', false, null, false, $parentProduct],
+            ]);
+
+        $cartItemData = [
+            [
+                'sku' => 'simple-1',
+                'parent_sku' => 'configurable-1',
+                'quantity' => 2,
+                'selected_options' => ['existing-option'],
+            ]
+        ];
+
+        $expected = [
+            [
+                'sku' => 'configurable-1',
+                'quantity' => 2,
+                'selected_options' => [base64_encode('configurable/1/1'), 'existing-option'],
+                'entered_options' => [],
+                'parent_sku' => null
+            ]
+        ];
+
+        $result = $this->precursor->process($cartItemData, $this->contextMock);
+
+        $this->assertEquals($expected, $result);
+        $this->assertEmpty($this->precursor->getErrors());
+    }
+
+    /**
+     * Test processing with non-configurable parent product
+     *
+     * @return void
+     * @throws Exception
+     */
+    public function testProcessNonConfigurableParent(): void
+    {
+        $childProduct = $this->getMockProduct('simple-1');
+        $parentProduct = $this->getMockProduct('simple-parent', 'simple');
+
+        $this->productRepositoryMock->expects($this->exactly(2))
+            ->method('get')
+            ->willReturnMap([
+                ['simple-1', false, null, false, $childProduct],
+                ['simple-parent', false, null, false, $parentProduct],
+            ]);
+
+        $cartItemData = [
+            [
+                'sku' => 'simple-1',
+                'parent_sku' => 'simple-parent',
+                'quantity' => 1
+            ]
+        ];
+
+        $result = $this->precursor->process($cartItemData, $this->contextMock);
+
+        $this->assertEquals($cartItemData, $result);
+        $this->assertCount(1, $this->precursor->getErrors());
+        $this->assertStringContainsString('not a configurable product', $this->precursor->getErrors()[0]['message']);
+    }
+
+    /**
+     * Test processing with no matching attributes
+     *
+     * @return void
+     * @throws Exception
+     */
+    public function testProcessNoMatchingAttributes(): void
+    {
+        $childProduct = $this->getMockProduct('simple-1');
+        $childProduct->method('getData')
+            ->willReturn([]); // Empty array to represent no matching attributes
+
+        $productAttributeMock = $this->createMock(AbstractAttribute::class);
+        $productAttributeMock->method('getAttributeId')->willReturn('1');
+        $productAttributeMock->method('getAttributeCode')->willReturn('color');
+
+        $attributeMock = $this->getMockBuilder(Attribute::class)
+            ->disableOriginalConstructor()
+            ->addMethods(['getProductAttribute'])
+            ->getMock();
+        $attributeMock->method('getProductAttribute')->willReturn($productAttributeMock);
+
+        $attributesCollection = [$attributeMock];
+
+        $configurableTypeMock = $this->createMock(Configurable::class);
+        $configurableTypeMock->method('getConfigurableAttributes')->willReturn($attributesCollection);
+
+        $parentProduct = $this->getMockProduct('configurable-1', Configurable::TYPE_CODE);
+        $parentProduct->method('getTypeInstance')->willReturn($configurableTypeMock);
+
+        $this->productRepositoryMock->expects($this->exactly(2))
+            ->method('get')
+            ->willReturnMap([
+                ['simple-1', false, null, false, $childProduct],
+                ['configurable-1', false, null, false, $parentProduct],
+            ]);
+
+        $cartItemData = [
+            [
+                'sku' => 'simple-1',
+                'parent_sku' => 'configurable-1',
+                'quantity' => 1
+            ]
+        ];
+
+        $result = $this->precursor->process($cartItemData, $this->contextMock);
+
+        $this->assertEquals($cartItemData, $result);
+        $this->assertCount(1, $this->precursor->getErrors());
+        $this->assertStringContainsString('Could not match child product', $this->precursor->getErrors()[0]['message']);
+    }
+
+    /**
+     * Test processing with product not found exception
+     *
+     * @return void
+     */
+    public function testProcessProductNotFound(): void
+    {
+        $this->productRepositoryMock->method('get')
+            ->willThrowException(new NoSuchEntityException(__('Product not found')));
+
+        $cartItemData = [
+            [
+                'sku' => 'unknown',
+                'parent_sku' => 'unknown-parent',
+                'quantity' => 1
+            ]
+        ];
+
+        $result = $this->precursor->process($cartItemData, $this->contextMock);
+
+        $this->assertEquals($cartItemData, $result);
+        $this->assertCount(1, $this->precursor->getErrors());
+        $this->assertStringContainsString('Product not found', $this->precursor->getErrors()[0]['message']);
+    }
+
+    /**
+     * Create mock product
+     *
+     * @param string $sku Product SKU
+     * @param string $typeId Product type ID
+     * @return ProductInterface
+     * @throws Exception
+     */
+    private function getMockProduct(string $sku, string $typeId = 'simple'): ProductInterface
+    {
+        $product = $this->getMockBuilder(ProductInterface::class)
+            ->addMethods(['getData', 'getTypeInstance'])
+            ->onlyMethods(['getSku', 'getTypeId', 'getId'])
+            ->disableOriginalConstructor()
+            ->getMockForAbstractClass();
+        $product->method('getSku')->willReturn($sku);
+        $product->method('getTypeId')->willReturn($typeId);
+        $product->method('getId')->willReturn(rand(1, 100));
+        return $product;
+    }
+}
diff --git a/app/code/Magento/QuoteGraphQl/etc/graphql/di.xml b/app/code/Magento/QuoteGraphQl/etc/graphql/di.xml
index eca1b68354e75..86be288de25e8 100644
--- a/app/code/Magento/QuoteGraphQl/etc/graphql/di.xml
+++ b/app/code/Magento/QuoteGraphQl/etc/graphql/di.xml
@@ -106,4 +106,11 @@
             </argument>
         </arguments>
     </type>
+    <type name="Magento\QuoteGraphQl\Model\CartItem\PrecursorComposite">
+        <arguments>
+            <argument name="precursors" xsi:type="array">
+                <item name="configurableProductPrecursor" xsi:type="object">Magento\QuoteGraphQl\Model\CartItem\Precursor\ConfigurableProductPrecursor</item>
+            </argument>
+        </arguments>
+    </type>
 </config>