Ford B series

The Ford B series is a bus chassis that was manufactured by the Ford Motor Company. Produced across six generations from 1948 to 1998, the B series was a variant of the medium-duty Ford F series. As a cowled-chassis design, the B series was a bare chassis aft of the firewall, intended for bodywork from a second-stage manufacturer. While primarily used for school bus applications in the United States and Canada, the chassis was exported worldwide to manufacturers to construct bus bodies for various uses.

Prior to 1969, Lincoln-Mercury dealers in Canada marketed the B series as part of the Mercury M-series truck line. At the time, rural Canadian communities were serviced by either a Ford or a Lincoln-Mercury dealer network, but not both networks concurrently.

Coinciding with the late 1996 sale of the Louisville/AeroMax heavy-truck line to Sterling Trucks, Ford phased out the medium-duty F series and the B series following the 1998 model year. For 2000, Ford re-entered the medium-duty segment with the F-650/F-750 Super Duty. As of the 2019 model year, Ford has not developed a cowled-chassis derivative of the F series, instead concentrating on cutaway chassis vehicles. In the cowled-chassis segment, the role and market share of the B series was largely superseded by the Blue Bird Vision (introduced in late 2000's).