The Douglas DC-8 is a four-engined narrow-body passenger commercial jet airliner, manufactured from 1958 to 1972 by the Douglas Aircraft Company. Launched later than the competing Boeing 707, the DC-8 nevertheless established Douglas in a strong position in the airliner market, and remained in production until 1972 when it began to be superseded by much larger designs, including the DC-10 and Boeing 747. The DC-8 design allowed it to hold slightly more cargo than the 707. Dozens of re-engined examples remain in freighter service to this day, while commercial 707 service had largely ended by 2000.

In the post-World War II era, Douglas held a commanding position in the commercial aircraft market. Although Boeing had pointed the way to the modern all-metal airliner in 1933 with the 247, it was Douglas that, more than any other company, had made commercial air travel a reality. Douglas produced a succession of piston-engined aircraft (DC-2, DC-3, DC-4, DC-5, DC-6, and DC-7) through the 1930s, 1940s and 1950s.