Samaire Rhys Armstrong (born October 31, 1980 in Tokyo, Japan) is an American television actress, best known for her roles as Emily on Entourage and as Anna Stern on The O.C.. Her name is pronounced sɑmɪːrɑ.

Armstrong was born in Japan and lived there for several years before moving to Hawaii and later Sedona, Arizona where she grew up. Armstrong attended the University of Arizona, but dropped out because of the school drama department's policy of barring freshmen from involvement in productions. Afterwards, she moved to Los Angeles.

Her first major break into film acting was as one half of the conjoined twins the Fratelli sisters in the parody movie "Not Another Teen Movie". Armstrong also had a recurring role on Freaks and Geeks, and had guest appearances on Judging Amy, Party of Five, and the X-Files. She was romantically linked to Aaron Paul. Armstrong appeared in The O.C. for one episode, and was brought back at fan request for several episodes of the first season. She can be currently seen on the HBO Television Series Entourage. Her most recent projects include the films Stay Alive, Just My Luck and Rise. She has since returned to The O.C. starting episode 22 of season 3.

When not acting, Armstrong is often designing clothes for her own clothing brand called NARU. She has also appeared in music videos such as in Hanson's Penny and Me and Daniel Powter's Bad Day.