Khojak Tunnel (aka Sheilla Bagh Tunnel) is a 3.91 kilometres long railway tunnel located in Killa Abdullah district of Balochistan (Province of Pakistan), near Pak-Afghan border at Chamman.It is located 1,945 metres above sea level.
The tunnel was constructed in 1891 under the Khojak Pass and remains one of the longest tunnels in South Asia, and the longest in Pakistan. It is expected to be surpassed by the 8.6 km Lowari Tunnel, currently under construction, in 2009.
It was featured on the old Rs. 5 banknote.