Kathy Brier (born March 10, 1975) is an American stage and television actress. She was born on Staten Island in New York.

She started playing the bit role of Marcie Walsh on the soap opera One Life to Live in 2002. Her character served little purpose other than a confidante to a villainess on the show, Jennifer Rappaport (played by Jessica Morris). However, her more zaftig appearance (she has been quoted in soap periodicals as taking a size 10 or 12 dress) resonated with viewers, who wished to see her more often. Her story was expanded, giving her a job as secretary in the Llanview Police Department. She even got a love interest, in the form of reformed bad-boy Al Holden (Nathaniel Marston). The couple's popularity quickly soared, and the two were voted Most Popular Couple in various soap magazines for months on end.

Late in 2003, she took over the role of Tracy Turnblad in the Broadway production of Hairspray; before that time, she had been an understudy to the role. She exited the role in May 2004.

For the purposes of removing actors James DePaiva as Max Holden (1987-1990, 1992-2003) and Fiona Hutchison as Gabrielle Medina (1987-1991, 2001-2004), Marcie's love interest was killed off in 2003. This prompted a great deal of negative feedback from soap fans and Nathaniel Marston was rehired with the show but took on a new character names Michael McBain who was also paired with Marcie. The Marcie & Michael pairing has not been an instant hit with fans leaving some viewers questing the future the show. In 2004 headwriter Michael Malone was fired from One Life to Live and Days of Our Lives scribe writer Dena Higley took over. Higley has taken the position that Marcie and Michael can work but they were brought together too quickly for fans to belive there romance. Kathy's future on the show is now looking up as Marcie has recently signed a new extended contract.

Kathy was nominated for a Daytime Emmy Award for "Outstanding Supporting Actress in a Drama Series" with co-star Ilene Kristen in 2004.