The women's foil B wheelchair fencing competition at the 2012 Summer Paralympics was held on 4 September at the ExCeL Exhibition Centre. The tournament started with a group phase round-robin followed by a knockout stage. During a qualification round-robin, bouts lasted a maximum of three minutes, or until one athlete had scored five hits. There was then a knockout phase, in which bouts lasted a maximum of nine minutes (three periods of three minutes), or until one athlete had scored 15 hits. The event was won by , representing China.