Sasha Embeth Pieterse (born on February 17, 1996) is a South African-born American actress.

Born in Johannesburg, South Africa, Pieterse was raised in Las Vegas, Nevada before moving to Los Angeles with her parents. Besides acting, Pieterse enjoys singing, chatting with her friends on gmail, jewelery making and photography.

She began acting in 2000, when she was given a role as one of the Davis children on the Warner Brothers's canceled remake of the popular show Family Affair. In 2004, she appeared in Stargate SG-1 as well as Andie in the second season episode "Autopsy" of Fox's House. In 2005, she appeared in her first film The Adventures of Shark Boy and Lava Girl and also in a short-lived series called Wanted with her former Family Affair co-star, Gary Cole.

During her appearance as a cancer patient on House, her long curly hair was hidden under a special latex fake scalp[citation needed]. She was submitted for Emmy Award consideration for her guest-starring role.

Pieterse was cast as Alison DiLaurentis in the TV series Pretty Little Liars based on the book series by Sara Shepard. Being only 14, she is the youngest actress on the show, because all of her co-stars are in their early 20s.

In January 2011, Pieterse portayed a teenage Marie Dubois in the series final of Medium.