Shelley was first used as a girls' name by the actress Shelley Winters (born Shirley Schrift, 1920-2006). She used Shelley as a stage name after the poet Percy Bysshe Shelley. It became popular in the middle part of the 20th century along with similar names like Kelly and Michelle. It is sometimes used as a pet form of Michelle. It is also found in the alternate spellings Shelli, Sheli, Shellie, Shelly etc.