The jetliner was designed to bridge the gap between Boeing's other wide body airplanes, the twin-engined 767 and quad-engined 747, and to replace aging DC-10s and L-1011 trijets. Developed in consultation with eight major airlines, the 777 program was launched in October 1990, with an order from United Airlines.

The Boeing 777 (Triple Seven) was specifically designed to "bridge the gap" in Boeing's lineup and replace a generation of aging three-engined "tri-jets" and early wide-bodies. Its primary targets for replacement were the McDonnell Douglas DC-10 and the Lockheed L-1011 TriStar. These older planes were less fuel-efficient and required more maintenance due to their third engine mounted in the tail. The 777 also eventually replaced many Boeing 747-100 and 747-200 models on routes where the "Jumbo Jet" was too large to be profitable but the smaller 767 didn't have enough range or capacity. By utilizing two massive, highly efficient engines (like the GE90), the 777 proved that a twin-engine plane could safely cross the ocean (ETOPS) with the same reliability as a three- or four-engine jet. In 2026, as the newer 777X begins to enter service, the original 777-200 and 777-300 models are themselves being phased out in favor of even more efficient twin-jets like the 787 Dreamliner and Airbus A350.