diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2f78c9ee..d296a0bd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@
 - Fixed Relay returning server errors as error responses and raw error messages without stack traces (#1292)
 - Fixed Relay reconnecting after an explicit disconnect (#1292)
 - Fixed Relay ACL authentication accepting username and password (#1292)
+- Fixed Relay throwing a `TypeError` instead of returning an error response when selecting a non-integer database (#1751)
 - Fixed `INFO` parsing warnings with Valkey 9 (#1748)
 
 ## v3.7.0 (2026-10-08)
diff --git a/src/Connection/RelayConnection.php b/src/Connection/RelayConnection.php
index 5d4d462d..ecba1988 100644
--- a/src/Connection/RelayConnection.php
+++ b/src/Connection/RelayConnection.php
@@ -12,10 +12,13 @@
 
 namespace Predis\Connection;
 
+use TypeError;
+use ArgumentCountError;
 use InvalidArgumentException;
 use Predis\ClientException;
 use Predis\Command\CommandInterface;
 use Predis\NotSupportedException;
+use Predis\Response\Error as ErrorResponse;
 use Predis\Response\ErrorInterface as ErrorResponseInterface;
 use Predis\Response\ServerException;
 use Relay\Exception as RelayException;
@@ -204,6 +207,10 @@ class RelayConnection extends AbstractConnection
                 $arguments = [$arguments];
             }
 
+            if ($name === 'SELECT') {
+                return $this->select($arguments);
+            }
+
             // Raw dispatch leaves values untouched. Serialization and compression
             // are applied explicitly with pack() and unpack().
             return in_array($name, $this->atypicalCommands)
@@ -222,6 +229,24 @@ class RelayConnection extends AbstractConnection
         }
     }
 
+    /**
+     * Relay's select() throws a TypeError for a non-integer database, where
+     * other connections get an error response from the server.
+     *
+     * @param  array $arguments
+     * @return mixed
+     */
+    protected function select(array $arguments)
+    {
+        try {
+            return $this->client->select(...$arguments);
+        } catch (ArgumentCountError $ex) {
+            throw $ex;
+        } catch (TypeError $ex) {
+            return new ErrorResponse('ERR value is not an integer or out of range');
+        }
+    }
+
     /**
      * {@inheritdoc}
      */
diff --git a/tests/Predis/Command/Redis/SELECT_Test.php b/tests/Predis/Command/Redis/SELECT_Test.php
index 551c72c7..76e223c0 100644
--- a/tests/Predis/Command/Redis/SELECT_Test.php
+++ b/tests/Predis/Command/Redis/SELECT_Test.php
@@ -83,9 +83,42 @@ class SELECT_Test extends PredisCommandTestCase
         $redis->select(100000000);
     }
 
+    /**
+     * Relay warns before sending SELECT for indexes beyond `relay.databases`,
+     * which PHPUnit would turn into an exception before the server replies.
+     *
+     * @group connected
+     */
+    public function testThrowsExceptionOnUnexpectedDatabaseRangeDespiteRelayWarning(): void
+    {
+        if (!getenv('USE_RELAY')) {
+            $this->markTestSkipped('Relay only warns when it is the active connection.');
+        }
+
+        $this->expectException('Predis\Response\ServerException');
+        $this->expectExceptionMessageMatches('/ERR.*DB index/');
+
+        $redis = $this->getClient();
+
+        $previous = set_error_handler(
+            static function ($level, $message, $file = '', $line = 0) use (&$previous) {
+                if (strpos($message, 'in-memory databases') !== false) {
+                    return true;
+                }
+
+                return $previous ? $previous($level, $message, $file, $line) : false;
+            }
+        );
+
+        try {
+            $redis->select(100000000);
+        } finally {
+            restore_error_handler();
+        }
+    }
+
     /**
      * @group connected
-     * @group relay-incompatible
      */
     public function testThrowsExceptionOnUnexpectedDatabaseName(): void
     {
diff --git a/tests/Predis/Connection/RelayConnectionTest.php b/tests/Predis/Connection/RelayConnectionTest.php
index 309e48cb..7c4b1b3a 100644
--- a/tests/Predis/Connection/RelayConnectionTest.php
+++ b/tests/Predis/Connection/RelayConnectionTest.php
@@ -12,6 +12,7 @@
 
 namespace Predis\Connection;
 
+use ArgumentCountError;
 use PHPUnit\Framework\MockObject\MockObject;
 use Predis\Client;
 use Predis\ClientException;
@@ -24,6 +25,7 @@ use PredisTestCase;
 use ReflectionClass;
 use Relay\Exception as RelayException;
 use Relay\Relay;
+use TypeError;
 
 /**
  * @group ext-relay
@@ -166,6 +168,72 @@ class RelayConnectionTest extends PredisTestCase
         $this->assertTrue($response);
     }
 
+    /**
+     * @group disconnected
+     * @return void
+     */
+    public function testExecuteSelectOnClient(): void
+    {
+        $this->mockClient
+            ->expects($this->once())
+            ->method('isConnected')
+            ->withAnyParameters()
+            ->willReturn(true);
+
+        $this->mockClient
+            ->expects($this->once())
+            ->method('SELECT')
+            ->with(1)
+            ->willReturn(true);
+
+        $response = $this->connection->executeCommand(new RawCommand('SELECT', [1]));
+
+        $this->assertTrue($response);
+    }
+
+    /**
+     * @group disconnected
+     * @return void
+     */
+    public function testExecuteSelectReturnsErrorResponseOnNonIntegerDatabase(): void
+    {
+        $this->mockClient
+            ->expects($this->once())
+            ->method('isConnected')
+            ->withAnyParameters()
+            ->willReturn(true);
+
+        $this->mockClient
+            ->method('SELECT')
+            ->willThrowException(new TypeError('Argument #1 ($db) must be of type int, string given'));
+
+        $response = $this->connection->executeCommand(new RawCommand('SELECT', ['x']));
+
+        $this->assertInstanceOf(ErrorResponse::class, $response);
+        $this->assertSame('ERR value is not an integer or out of range', (string) $response);
+    }
+
+    /**
+     * @group disconnected
+     * @return void
+     */
+    public function testExecuteSelectDoesNotHideArgumentCountError(): void
+    {
+        $this->mockClient
+            ->expects($this->once())
+            ->method('isConnected')
+            ->withAnyParameters()
+            ->willReturn(true);
+
+        $this->mockClient
+            ->method('SELECT')
+            ->willThrowException(new ArgumentCountError('Too few arguments'));
+
+        $this->expectException(ArgumentCountError::class);
+
+        $this->connection->executeCommand(new RawCommand('SELECT', []));
+    }
+
     /**
      * @group disconnected
      * @return void