The Heinkel He 177 Greif (Griffin) was a long-range heavy bomber flown by the Luftwaffe during World War II. The introduction of the He 177 to combat operations was significantly delayed, by both problems with the development of its engines and frequent changes to its intended role. Nevertheless, it was the only long-range, heavy bomber to become operational with the Luftwaffe during the war. The He 177 had a payload/range capability similar to that of four-engined heavy bombers used by the Allies in the European theatre.

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 In the second half of the 20th century, heavy bombers were largely superseded by strategic bombers, which were often even larger in size, had much longer ranges and were capable of delivering nuclear bombs.