It opened on November 2, 1925, as part of the extension of the line from Moor Park, and had solely electrical services from the London North East Railway as well as the Metropolitan. Although it is the final station in its branch it was not planned as such, the Watford High Street station was built but not connected to the Metropolitan system. Metropolitan services initially ran on northwards but these trains were cut in 1933.
A link from Croxley tube station to Watford Junction Station has been often proposed and would lead to the closure of this station. Watford Junction was connected to the Bakerloo Line in 1917 but the portion of the of the line from Harrow & Wealdstone to Watford Junction was closed in 1982.