The Boeing 737 is the world’s most-produced commercial jet aircraft.
Boeing developed the 737 as a smaller twin-engine companion to its larger 707 and 727 airliners. The first 737-100 flew in 1967, and Lufthansa began operating the type commercially in 1968. Its compact size, efficient operation, and ability to use shorter airport runways helped it become popular with airlines worldwide.
The 737 family includes several generations, from the original 737 Original series through the Classic, Next Generation, and 737 MAX families. Counting the family across its production history is essential: the record applies to the 737 line, not to one individual variant.
The Airbus A320 family is a major competitor and is also among the most-produced commercial aircraft families. However, the Boeing 737 is the canonical answer when the question asks for the most-produced commercial jet aircraft.