Simpsons is perhaps one of the oldest business establishments in the country, with origins dating back to 1840. From 1840 to 1950 it pioneered the building of coaches and carriages, ornate railway coaches, motorcars, steam passenger buses and public service vehicles in India.

Simpsons became synonymous with diesel power when it ushered in engine technology into India in 1951 through a Sales & Distribution Agreement with Perkins of U.K. Simpsons was the first Indian company to indigenously manufacture diesel engines for surface transport vehicles. Today it is India's leading manufacturer of high performance diesel engines catering to a wide variety of applications ranging from 15 to 95 BHP covering agriculture, industrial, power generation and marine applications.