diff --git a/ext/mysqli/tests/fake_server.inc b/ext/mysqli/tests/fake_server.inc
index 2a4d17f946e8..8fb2f5a4aeba 100644
--- a/ext/mysqli/tests/fake_server.inc
+++ b/ext/mysqli/tests/fake_server.inc
@@ -630,6 +630,15 @@ class my_mysqli_fake_server_conn
         fprintf(STDERR, "[*] Received: %s\n", bin2hex($data));
     }
 
+    public function read_compressed_packet(): void
+    {
+        $header = $this->read_bytes(7);
+        $compressed_length = ord($header[0]) | (ord($header[1]) << 8) | (ord($header[2]) << 16);
+        $uncompressed_length = ord($header[4]) | (ord($header[5]) << 8) | (ord($header[6]) << 16);
+        $this->read_bytes($compressed_length);
+        fprintf(STDERR, "[*] Received compressed packet: %d bytes, uncompressed length %d\n", $compressed_length, $uncompressed_length);
+    }
+
     public function close()
     {
         fclose($this->conn);
@@ -1445,6 +1454,19 @@ function my_mysqli_test_stmt_response_field_len_premature(my_mysqli_fake_server_
 	$conn->read(65536);
 }
 
+function my_mysqli_test_compressed_queries(my_mysqli_fake_server_conn $conn): void
+{
+    $conn->send_server_greetings();
+    $conn->read();
+    $conn->send_server_ok();
+    for ($i = 0; $i < 2; $i++) {
+        $conn->read_compressed_packet();
+        $ok = $conn->packet_generator->server_ok("01")->to_bytes();
+        $conn->send(substr(pack('V', strlen($ok)), 0, 3) . "\x01\x00\x00\x00" . $ok, "Compressed Server OK");
+    }
+    $conn->read_compressed_packet();
+}
+
 function run_fake_server(string $test_function, int|string $port = 0): void
 {
     $host = '127.0.0.1';
diff --git a/ext/mysqli/tests/mysqli_compression_threshold.phpt b/ext/mysqli/tests/mysqli_compression_threshold.phpt
new file mode 100644
index 000000000000..9c679c0da883
--- /dev/null
+++ b/ext/mysqli/tests/mysqli_compression_threshold.phpt
@@ -0,0 +1,43 @@
+--TEST--
+Compressed protocol: packets below the threshold are sent uncompressed
+--EXTENSIONS--
+mysqli
+--SKIPIF--
+<?php
+ob_start();
+if (extension_loaded('mysqlnd')) {
+    (new ReflectionExtension('mysqlnd'))->info();
+}
+if (!str_contains(ob_get_clean(), 'Compression => supported')) {
+    die('skip mysqlnd is built without compression support');
+}
+?>
+--FILE--
+<?php
+require_once 'fake_server.inc';
+
+$process = run_fake_server_in_background('compressed_queries');
+$process->wait();
+
+$link = mysqli_init();
+$link->real_connect('127.0.0.1', 'root', '', '', $process->getPort(), null, MYSQLI_CLIENT_COMPRESS);
+var_dump($link->query("SELECT '" . str_repeat('a', 80) . "'"));
+var_dump($link->query("SELECT '" . str_repeat('a', 1000) . "'"));
+$link->close();
+
+$process->terminate(true);
+?>
+--EXPECTF--
+[*] Server started on 127.0.0.1:%d
+[*] Connection established
+[*] Sending - Server Greeting: 580000000a352e352e352d31302e352e31382d4d6172696144420003000000473e3f6047257c6700fef7080200ff81150000000000000f0000006c6b55463f49335f686c6431006d7973716c5f6e61746976655f70617373776f7264
+[*] Received: %s
+[*] Sending - Server OK: 0700000200000002000000
+[*] Received compressed packet: 94 bytes, uncompressed length 0
+[*] Sending - Compressed Server OK: 0b0000010000000700000100000002000000
+bool(true)
+[*] Received compressed packet: %d bytes, uncompressed length 1014
+[*] Sending - Compressed Server OK: 0b0000010000000700000100000002000000
+bool(true)
+[*] Received compressed packet: 5 bytes, uncompressed length 0
+[*] Server finished
diff --git a/ext/mysqlnd/mysqlnd_protocol_frame_codec.c b/ext/mysqlnd/mysqlnd_protocol_frame_codec.c
index 70a81befdd71..2663a101ed0a 100644
--- a/ext/mysqlnd/mysqlnd_protocol_frame_codec.c
+++ b/ext/mysqlnd/mysqlnd_protocol_frame_codec.c
@@ -55,7 +55,8 @@ static ssize_t write_compressed_packet(
 	/* here we need to compress the data and then write it, first comes the compressed header */
 	size_t tmp_complen = to_be_sent;
 	size_t payload_size;
-	if (PASS == pfc->data->m.encode((compress_buf + COMPRESSED_HEADER_SIZE + MYSQLND_HEADER_SIZE), &tmp_complen,
+	if (to_be_sent >= MYSQLND_MIN_COMPRESS_LENGTH
+		&& PASS == pfc->data->m.encode((compress_buf + COMPRESSED_HEADER_SIZE + MYSQLND_HEADER_SIZE), &tmp_complen,
 							   uncompressed_payload, to_be_sent))
 	{
 		int3store(compress_buf + MYSQLND_HEADER_SIZE, to_be_sent);
diff --git a/ext/mysqlnd/mysqlnd_wireprotocol.h b/ext/mysqlnd/mysqlnd_wireprotocol.h
index ad452ec4f928..38bb4ce3c0bf 100644
--- a/ext/mysqlnd/mysqlnd_wireprotocol.h
+++ b/ext/mysqlnd/mysqlnd_wireprotocol.h
@@ -18,6 +18,8 @@
 
 #define MYSQLND_HEADER_SIZE 4
 #define COMPRESSED_HEADER_SIZE 3
+/* Packets smaller than this are sent uncompressed: they barely shrink. */
+#define MYSQLND_MIN_COMPRESS_LENGTH 100
 
 #define MYSQLND_NULL_LENGTH	(zend_ulong) ~0