Earl of Plymouth is a title that has been created three times: twice in the Peerage of England and once in the Peerage of the United Kingdom.

Charles FitzCharles, 1st Earl of Plymouth, was the illegitimate son of King Charles II of England and Catherine Pegge. He had a sister, Catherine, who is believed to have become a nun. His mother went on to marry Sir Edward Greene of Samford in Essex, and had one child, Justinia Greene. His subsidiary titles were Viscount Totness and Baron Dartmouth.