The 91 B-Line is a future express bus line with bus rapid transit elements in Metro Vancouver, Canada that was outlined in the 2005 Vancouver/UBC Transit Plan for implementation in December 2009. It will replace the 43 Express that travels along 41st Avenue, a major east-west route which connects the University of British Columbia (UBC) to Joyce Station on the SkyTrain system. The service will also connect with the Canada Line at Oakridge–41st Avenue station.
Shortfalls in the 2010 TransLink budget meant a delay in the implementation of 91 B-Line, the 95 B-Line (replacing 135 Express service on Hastings Street), and other service expansions. Nevertheless, the 43 Express service was included as a main transit connection in a plan released following the opening of the Canada Line, indicating the importance of the route within the Translink network.
On November 23, 2016, the Mayors' Council and TransLink's board of directors approved the first phase of the 10-Year Vision, which will see the launch of increased bus service, including the 91 B-Line, in April 2017.