The Diana Motors Company was an early United States automobile manufacturing company.

The company produced automobiles from 1925 to 1928. The St. Louis based company was a subsidiary of the Moon Motor Car company.

The Diana featured a Continental straight-8 engine and was primarily marketed to women. The car was billed as, "The easiest steering car in America". Prices for the 1925 model started at $1,895.

In Roman mythology Diana is goddess of the moon, which obviously was the reason for the name but, curiously, the company never dwelled on that fact much. It might be said that another goddess was involved as well, since the Diana’s radiator shell was virtual carbon copy of the Belgian Minerva. Diana / Moon did not dwell on that at all. The new company and the new car were announced by Stewart McDonald (president of Moon, who would hold the same position in Diana) in late May of 1925. The Diana itself arrived on June 25th, and was sensationally received. The company referred to it as “the easiest steering car in America,”

”the only car built entirely for balloon tires,” and “a car for women drivers.” In performance testing the Diana reported fuel consumption of 15 to 18 mpg. With maximum speeds up to 70mph. The car’s engine was a 72hp Continental straight-eight. It was as an up market motorcar of high style that the Diana truly shown.

Diana Motors claimed its “Composite Steel Body” to be a first, which is moot, though narrow steel windshield posts effectively enhanced visibility. Hydraulic four –wheel brakes were fitted as well as the Lanchester Vibration Dampener, both progressive features, though the Diana is perhaps better remembered for sporting one of the loveliest radiator mascots ever to appear on an American car.'