Stephanie DeFina Johnson (born March 8, 1946) is an American former amateur tennis player who was active in the 1960s and mid-1970s.

DeFina was included in the year-end top 10 rankings issued by the United States Lawn Tennis Association from 1966 through 1968, peaking at no.

[1][2] Her best singles result at a Grand Slam tournament was reaching the fourth round of the 1967 Wimbledon Championships, losing to Ann Jones.

In 1968, DeFina was a member of the U.S. team that competed for the Wightman Cup, the annual women's competition between the United States and Great Britain.

[4] Her other main career singles highlights include winning the South Florida Open Championships in West Palm Beach six times (1962–1964, 1966–1967, 1969).