The Birmingham and Oxford Junction Railway was an English railway line promoted by the Great Western Railway to gain a route from its southern base towards the industrial centres of the West Midlands, and in due course the north-west. It overtook another GWR subsidiary, the unbuilt Oxford and Rugby Railway, and the Birmingham Extension Railway which was to build a new independent station in the city. It was authorised in 1846 and formed a single project to connect Birmingham and Oxford.