David Trainer (July 9, 1814 - April 7, 1890) was an American textile manufacturer and banker from Chester, Pennsylvania.

[1] In 1837, Trainer, in association with John Haistings, Jr., changed the Old Price Grist Mill, which was owned by Trainer's father into a cotton factory.

[2] Trainer owned the "Linwood Mills", one of the largest textile factories in the region.

[3] Trainer was a director of the Delaware County National Bank and served as the third president from 1874 to 1875.

[5] Trainer was a churchwarden of the St. Martin's Church in Marcus Hook, Pennsylvania.