Dunsmuir Tunnel is a subway tunnel beneath Downtown Vancouver, British Columbia, Canada. Part of the Expo and Millennium SkyTrain lines, the tunnel is served by two stations: Burrard and Granville. The tunnel's west portal is located midway between Waterfront and Burrard Stations, while the east portal is immediately adjacent to Stadium–Chinatown Station.
The tunnel was originally built by the Northern Construction Company in 1932 connecting the Canadian Pacific Railway railyards on Burrard Inlet and False Creek at a cost of $1.6 million. The tunnel's east portal is located further south than the current portal, easing trains into the False Creek yards on a gentle southward curve. The former east portal is still present. It was clearly visible until about 2005 and is now almost completely hidden next to an outdoor storage area behind the Costco. There is now an abandoned portion of tunnel unused by SkyTrain at the former east portal.
The tunnel was taken over by BC Transit in the early 1980s when the SkyTrain system was built in conjunction with Expo 86. Because the tunnel is only wide enough to accommodate a single railway track but with sufficiently high clearance, a superstructure was built inside the tunnel to carry the westbound SkyTrain track above the eastbound track.