Horsham would have been an important midway point in two of the original proposals for a London to Brighton railway via the Adur valley but in the event Sir John Rennie's proposed direct line through Three Bridges (in east Crawley) and Haywards Heath was given parliamentary approval.

As a result, the original Horsham station was the terminus of a single track branch line from Three Bridges opened by the London Brighton and South Coast Railway (LBSCR) in February 1848.

[2] The present station was built by the Southern Railway in the International Modern Style in 1938 to coincide with the electrification of the line.

The lines to Guildford and Shoreham both fell victim to the Beeching Axe in the mid-1960s, the former being closed to passengers on 14 June 1965 and the latter on 7 March 1966.

In September 2011, the station frontage was closed to undergo extensive refurbishment work to the main ticket hall.

It reopened late in 2012 with a new side entrance, internal lift access, relocated barriers and stairway, a new ticket office, and new information screens.