Plymouth is a brand of automobile based in the United States marketed by Chrysler Corporation and DaimlerChrysler from 1928 to 2001. The Plymouth brand was first introduced on July 7, 1928 and was Chrysler's first entry in the low-priced field which was then dominated by Ford and Chevrolet. The Plymouth vehicles were priced a little higher than the competition because of its top-of-the-line Plymouth parts like hydraulic brakes that the competition doesn't provide. Plymouths were originally sold exclusively by Chrysler dealerships.

The first Plymouth can be traced back to the Maxwell automobile which Walter Chrysler inherited as part of taking over the Maxwell-Chalmers car company on 1920. He made use of the company's facilities to create and launch the Chrysler car in 1924. And in the year 1926 the Maxwell was rebadged and modified as a low-end Chrysler model. This model was again altered but this time it was created back into Plymouth.

The original purpose of the Plymouth was to provide low cost automobiles during the Great Depression that happened in 1930. The Plymouth helped the Chrysler Corporation survive a decade when many of other car companies failed. Three Chrysler divisions sold Plymouth beginning 1930 and these are as follows: Chrysler, DeSoto, and Dodge. Plymouths were selling quite well during such grim automotive period and in fact even rose to the number three spot among saleable cars by 1931.

During its lifetime, the Plymouth brand became one of America's top selling automobile brands together with Chevrolet and Ford. They were considered the low-priced three. By 1940s Plymouth was able to surpass Ford as the second most popular brand of automobiles in the US. Until 1956 Plymouth vehicles were famous for their durability, affordability and engineering. By 1957, Chrysler's Forward Look styling theme created cars that possessed more advanced styling than Chevrolet and Ford. However, Plymouth's reputation was put in a bad light since the cars they made were prone to rust and had sloppy assembly. Chrysler started its Forward Look Styling a year before when it introduced its limited production Fury line.

Plymouth's sale started to rapidly decline in the early 1960s due to awkwardly styled cars that they produced. But from 1957 to 1959, Plymouth was considered a styling leader. Another reason for Plymouth's demise was when it was made to compete with own corporate sister division Dodge which also launched a low-priced, full-size Dodge Dart in 1960. Afterwards Plymouth went into further decline as Rambler and Pontiac assumed the number three sales position for the remainder of the decade.

Plymouth was able to regain market share with the introduction of its 1965 models which included full-size vehicles with more mainstream styling. By 1971 and 1974 Plymouth was able to regain its number three spot in the sales race with its Valiant and Duster compact models. When Chrysler suffered financial difficulties in the 1970s Plymouth's lineup was reduced to the point that it was no longer a full-line make.