diff --git a/phpBB/includes/db/mssql.php b/phpBB/includes/db/mssql.php
index 7864f7a3d7..84e356efdd 100644
--- a/phpBB/includes/db/mssql.php
+++ b/phpBB/includes/db/mssql.php
@@ -34,9 +34,11 @@ class dbal_mssql extends dbal
 	{
 		$this->persistency = $persistency;
 		$this->user = $sqluser;
-		$this->server = $sqlserver . (($port) ? ':' . $port : '');
 		$this->dbname = $database;
 
+		$port_delimiter = (defined('PHP_OS') && substr(PHP_OS, 0, 3) === 'WIN') ? ',' : ':';
+		$this->server = $sqlserver . (($port) ? $port_delimiter . $port : '');
+
 		@ini_set('mssql.charset', 'UTF-8');
 		@ini_set('mssql.textlimit', 2147483647);
 		@ini_set('mssql.textsize', 2147483647);
diff --git a/phpBB/includes/db/mssql_odbc.php b/phpBB/includes/db/mssql_odbc.php
index d26dafdb52..af13c2dc70 100644
--- a/phpBB/includes/db/mssql_odbc.php
+++ b/phpBB/includes/db/mssql_odbc.php
@@ -40,9 +40,11 @@ class dbal_mssql_odbc extends dbal
 	{
 		$this->persistency = $persistency;
 		$this->user = $sqluser;
-		$this->server = $sqlserver . (($port) ? ':' . $port : '');
 		$this->dbname = $database;
 
+		$port_delimiter = (defined('PHP_OS') && substr(PHP_OS, 0, 3) === 'WIN') ? ',' : ':';
+		$this->server = $sqlserver . (($port) ? $port_delimiter . $port : '');
+
 		$max_size = @ini_get('odbc.defaultlrl');
 		if (!empty($max_size))
 		{