A stand-off breaching device (20) for breaching a barrier, comprising a housing (21), an explosive main charge (24) having a barrier-end (25) and a rear-end (26), a detonator (29), and means for initiating the detonator (27) when the explosive main charge (24) is at a preselected distance from a barrier. The detonator (29) is configured to detonate explosive main charge (24) at the rear-end (26) such that the resultant detonation wave propagates through the explosive main charge (24) towards the barrier-end (25) and the barrier being breached. This configuration provides more efficient transfer of explosively generated overpressure towards a barrier, thereby enabling the use of explosive main charges (24) with reduced mass, and the associated improvements in operator safety. The breaching device (20) is particularly suited to use in door breaching operations.