John Sylvester may refer to:

• John Sylvester (admiral) (1904–1990), United States Navy admiral
• John Sylvester (cricketer) (born 1969), Grenadian cricketer
• John N. Sylvester (1909–1993), American politician in the state of Washington
• John B. Sylvester, United States Army general
• Johnny Sylvester (1915–1990), American businessman associated with Babe Ruth
• John Sylvester, one of the pen names of British author Hector Hawton (1901–1975)