diff --git a/spanner/src/batch_write.php b/spanner/src/batch_write.php
new file mode 100644
index 0000000000..79a46e5fec
--- /dev/null
+++ b/spanner/src/batch_write.php
@@ -0,0 +1,138 @@
+<?php
+/**
+ * Copyright 2026 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * For instructions on how to run the full sample:
+ *
+ * @see https://github.com/GoogleCloudPlatform/php-docs-samples/tree/main/spanner/README.md
+ */
+
+namespace Google\Cloud\Samples\Spanner;
+
+// [START spanner_batch_write_at_least_once]
+use Google\Cloud\Spanner\SpannerClient;
+use Google\Cloud\Spanner\V1\Mutation;
+use Google\Cloud\Spanner\V1\Mutation\Write;
+use Google\Cloud\Spanner\V1\BatchWriteRequest\MutationGroup;
+
+/**
+ * Inserts sample data into the given database via BatchWrite API.
+ * The database and table must already exist and can be created using `create_database`.
+ *
+ * Example:
+ * ```
+ * batch_write($projectId, $instanceId, $databaseId);
+ * ```
+ *
+ * @param string $projectId The Google Cloud project ID.
+ * @param string $instanceId The Spanner instance ID.
+ * @param string $databaseId The Spanner database ID.
+ */
+function batch_write(string $projectId, string $instanceId, string $databaseId): void
+{
+    $spanner = new SpannerClient(['projectId' => $projectId]);
+    $database = $spanner->instance($instanceId)->database($databaseId);
+
+    // Create Mutation Groups
+    // All mutations within a single group are applied atomically.
+    // Mutations across groups are applied non-atomically.
+
+    // Group 1: Single mutation
+    $mutationGroup1 = new MutationGroup([
+        'mutations' => [
+            new Mutation([
+                'insert_or_update' => new Write([
+                    'table' => 'Singers',
+                    'columns' => ['SingerId', 'FirstName', 'LastName'],
+                    'values' => [
+                        [16, 'Scarlet', 'Terry']
+                    ]
+                ])
+            ])
+        ]
+    ]);
+
+    // Group 2: Multiple mutations
+    $mutationGroup2 = new MutationGroup([
+        'mutations' => [
+            new Mutation([
+                'insert_or_update' => new Write([
+                    'table' => 'Singers',
+                    'columns' => ['SingerId', 'FirstName'],
+                    'values' => [
+                        [17, 'Marc']
+                    ]
+                ])
+            ]),
+            new Mutation([
+                'insert_or_update' => new Write([
+                    'table' => 'Singers',
+                    'columns' => ['SingerId', 'FirstName', 'LastName'],
+                    'values' => [
+                        [18, 'Catalina', 'Smith']
+                    ]
+                ])
+            ]),
+            new Mutation([
+                'insert_or_update' => new Write([
+                    'table' => 'Albums',
+                    'columns' => ['SingerId', 'AlbumId', 'AlbumTitle'],
+                    'values' => [
+                        [17, 1, 'Total Junk']
+                    ]
+                ])
+            ]),
+            new Mutation([
+                'insert_or_update' => new Write([
+                    'table' => 'Albums',
+                    'columns' => ['SingerId', 'AlbumId', 'AlbumTitle'],
+                    'values' => [
+                        [18, 2, 'Go, Go, Go']
+                    ]
+                ])
+            ])
+        ]
+    ]);
+
+    $responses = $database->batchWriteAtLeastOnce([$mutationGroup1, $mutationGroup2], [
+        'requestOptions' => ['transactionTag' => 'batch-write-tag']
+    ]);
+
+    // Check the response code of each response to determine whether the mutation group(s) were applied successfully.
+    foreach ($responses as $response) {
+        $status = $response->getStatus();
+        $indexes = implode(', ', iterator_to_array($response->getIndexes()));
+        if ($status->getCode() === 0) {
+            $timestamp = $response->getCommitTimestamp();
+            printf('Mutation group indexes [%s] have been applied with commit timestamp %s' . PHP_EOL,
+                $indexes,
+                $timestamp ? $timestamp->getSeconds() : 'Unknown'
+            );
+        } else {
+            printf('Mutation group indexes [%s] could not be applied with error code %s and error message %s' . PHP_EOL,
+                $indexes,
+                $status->getCode(),
+                $status->getMessage()
+            );
+        }
+    }
+}
+// [END spanner_batch_write_at_least_once]
+
+// The following 2 lines are only needed to run the samples
+require_once __DIR__ . '/../../testing/sample_helpers.php';
+\Google\Cloud\Samples\execute_sample(__FILE__, __NAMESPACE__, $argv);
diff --git a/spanner/test/spannerBatchWriteTest.php b/spanner/test/spannerBatchWriteTest.php
new file mode 100644
index 0000000000..412cd59722
--- /dev/null
+++ b/spanner/test/spannerBatchWriteTest.php
@@ -0,0 +1,70 @@
+<?php
+/**
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Google\Cloud\Samples\Spanner;
+
+use Google\Cloud\Spanner\SpannerClient;
+use Google\Cloud\TestUtils\EventuallyConsistentTestTrait;
+use Google\Cloud\TestUtils\TestTrait;
+use PHPUnitRetry\RetryTrait;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @retryAttempts 3
+ * @retryDelayMethod exponentialBackoff
+ */
+class spannerBatchWriteTest extends TestCase
+{
+    use TestTrait {
+        TestTrait::runFunctionSnippet as traitRunFunctionSnippet;
+    }
+
+    use RetryTrait, EventuallyConsistentTestTrait;
+
+    /** @var string instanceId */
+    protected static $instanceId;
+
+    /** @var string databaseId */
+    protected static $databaseId;
+
+    public static function setUpBeforeClass(): void
+    {
+        if (!extension_loaded('grpc')) {
+            self::markTestSkipped('Must enable grpc extension.');
+        }
+        self::$instanceId = self::requireEnv('GOOGLE_SPANNER_INSTANCE_ID');
+        self::$databaseId = self::requireEnv('GOOGLE_SPANNER_DATABASE_ID');
+    }
+
+    /**
+     * @test
+     */
+    public function testBatchWrite()
+    {
+        $output = $this->runFunctionSnippet('batch_write');
+        $this->assertStringContainsString('Mutation group indexes', $output);
+        $this->assertStringContainsString('have been applied', $output);
+    }
+
+    private function runFunctionSnippet($sampleName, $params = [])
+    {
+        return $this->traitRunFunctionSnippet(
+            $sampleName,
+            array_merge([self::$projectId, self::$instanceId, self::$databaseId], array_values($params))
+        );
+    }
+}