Mary Caroline Pierce (born 15 January 1975) is a retired tennis professional. She represented France internationally in team competitions and in the Olympics.
Pierce won four Grand Slam titles: two in singles, one in doubles and one in mixed doubles. She reached six Grand Slam singles finals, most recently at the US Open and French Open in 2005. Her Grand Slam singles titles came at the 1995 Australian Open and the 2000 French Open; Pierce is the last French player, male or female, to win the latter title. She won the doubles event at the 2000 French Open with Martina Hingis as her partner, and reached an additional Grand Slam womens doubles final at the 2000 Australian Open, also partnering Hingis. She also won the mixed doubles event at the 2005 Wimbledon Championships, partnering with Mahesh Bhupathi. Pierce won 18 WTA singles titles and 10 WTA doubles titles, including five Tier I singles events. She also twice reached the final of the season-ending WTA Tour Championships, most recently in 2005.