Fort William Junction is a railway junction on the West Highland Line in Scotland, located to the east of Fort William railway station. It is where the railway to Mallaig connects with the Glasgow to Fort William railway.
A crossing loop exists on the Mallaig line immediately beyond the junction but there has never been a facility for crossing trains on the main West Highland Line in the vicinity of the junction.
Originally named "Banavie Junction", the junction was formed on 1 June 1895 when a short branch line to Banavie Pier was opened. The branch left the West Highland Railway approximately one mile east of Fort William station.
The junction was renamed "Mallaig Junction" on 30 March 1901, when the Mallaig Extension Railway opened. The former name "Banavie Junction" was however transferred concurrently to a new junction formed where the Mallaig railway left the existing branch to Banavie Pier. On 27 March 1988, the junction assumed its present name, "Fort William Junction", to avoid potential confusion with "Mallaig" in radio communications.
The Pier Railway of the Lochaber Narrow Gauge Railway originally crossed over the West Highland Railway and the Mallaig Extension Railway on separate bridges to the east of Mallaig Junction. Construction of a realigned Pier Railway, avoiding the site of Inverlochy village, commenced in 1927. It crossed the West Highland Railway on a bridge immediately west of Mallaig Junction. This bridge is still in situ but devoid of track following the complete closure of the narrow gauge line.
From its opening in 1894, the West Highland Railway was worked throughout by the electric token system. Banavie Junction signal box (as originally named) opened on 6 August 1894. The signal box is located in the vee of the junction and remains operational today. It has been renamed twice during its existence, in line with the junction itself.