Sarah Cassandra Chalke (born August 27, 1976) is a Canadian actress with dual American and Canadian citizenship, best known for portraying Dr. Elliot Reid on the NBC comedy Scrubs, Becky Conner Healy on Roseanne, and Stella Zinman in the CBS sitcom How I Met Your Mother.

Chalke was born in Ottawa, Ontario, Canada and was raised in Vancouver, British Columbia. She is the middle of the three daughters of Douglas and Angie Chalke. Her mother is originally from Rostock, Germany. According to a Scrubs commentary track, she used to attend the German school in her hometown twice a week. Her first language is English, although she speaks French fairly well and German fluently. Chalke graduated from Handsworth Secondary School in North Vancouver in 1994.

Her father is a lawyer in private practice in Vancouver. Her parents operate an adoption agency that specializes in placing foreign orphans (primarily Chinese) with Canadian families. Her older sister Natasha is also a lawyer, and she has a younger sister named Piper. In April 2008 Chalke became a naturalized American citizen.