Willesden Traction Maintenance Depot (TMD) is a railway locomotive and electric multiple unit traction maintenance depot, situated in Harlesden, north London.

The depot is situated next to the West Coast Main Line, to the south-east of Willesden Junction station and on the way into London Euston station.

The original locomotive servicing facility at Willesden was on the south side of the main line, west of the station, which closed in 1965.

There is also a road that runs round to the north of the shed, which provides access to the fuel siding; for many years, this was used only for the occasional fuelling of diesel shunters and also to the DC lines of Willesden Junction Low Level station, which is used to move multiple units from the shed onto the North London Line after servicing.

In more recent years, especially since the loss of AC electric locomotives, the fuel siding was promoted to other train operators as a facility at Willesden and a means to generate some revenue, this meant for instance that Gospel Oak to Barking line DMUs did not need to travel to Bletchley TMD and back each night for 'A' examinations and fuelling which could instead be carried out at Willesden.