The A642 is an A-road in West Yorkshire, England which runs from Huddersfield to the A64 near Leeds. It connects with the M1, M62 and A63.

The road begins at Waterloo east of the town centre before going on via Lepton, Grange Moor, Middlestown, Horbury(where it is the horbury bypass) into Wakefield City Centre.

The road then goes onwards via Stanley, M62 Motorway (Junction 30), Oulton, Swillington, Garforth through before meeting the M1 Motorway at Junction 47.

It also connects with the A656 (Jct 47), A639 (Oulton), B6135, A61 (Wakefield City Centre), B6475, B6128 (Horbury), B6117 (Horbury Bridge), A637 and B6118 (Grange Moor) and B6433 (Lepton) roads.