The Handley Page Halifax is a British Royal Air Force (RAF) four-engined heavy bomber of the Second World War. It was developed by Handley Page to the same specification as the contemporary twin-engine Avro Manchester.

Heavy bombers are bomber aircraft capable of delivering the largest payload of air-to-ground weaponry and longest range of their era. Archetypal heavy bombers have therefore usually been among the largest and most powerful military aircraft at any point in time. In the second half of the 20th century, heavy bombers were largely superseded by strategic bombers, which were often even larger in size, had much longer ranges and were capable of delivering nuclear bombs.