The station was opened by the London and Birmingham Railway as ’Harrow’ on 20 July 1837. At the time the station was built, the area was rural and the nearest large settlement was at Harrow on the Hill about 1.5 miles to the south. Wealdstone was then a collection of houses at the north end of what is now Wealdstone High Street, about one mile north of the station.

By the end of the 19th century Wealdstone had developed in size and the station was given its current name on 1 May 1897 to reflect more accurately its location.

On 18 December 1890, a short branch line to Stanmore was opened by the London & North Western Railway and on 16 April 1917, Bakerloo line services were extended from Willesden Junction to Watford Junction running on the newly electrified local tracks.

In 1952, the passenger service to Stanmore was withdrawn.

After 1984, Harrow & Wealdstone became the northern terminus of the Bakerloo line.

The Harrow and Wealdstone rail crash of 1952, which killed 112 people, occurred at the station and remains Britain’s worst peacetime rail disaster.