National Passenger Services, d/b/a Stock Transportation, is a Canadian school bus operator based in Markham, Ontario.

The company provides student transportation and charter services for twenty-eight school districts in Ontario, Nova Scotia and Alberta.

In July 2002, Stock Transportation was acquired by National Express, now known as Mobico Group.

In August 2024, Mobico announced it had formally began the sale process for its North American bus division, which includes Stock Transportation.

All of National Passenger Service's buses are equipped with Zonar GPS technology which enables their staff to observe real-time the position of all of their bus fleet.