Rachel Emily Nichols is an American actress and model from Augusta, Maine.

She is of English, Scotch-Irish, German, Italian and Scottish descent.

Nichols began modeling while attending Columbia University in New York City. She transitioned into television and film acting in the early 2000s; she had a part in the romantic drama film Autumn in New York (2000) and a one-episode role in Season 4 of the show Sex and the City (2002).

Her first major role was in the comedy film Dumb and Dumberer: When Harry Met Lloyd (2003). She had the main role in the crime drama television series The Inside (2005), though it was cancelled after one season. Nichols gained recognition playing Rachel Gibson in the final season of the serial action television series Alias (2005–2006) and for her role in the horror film The Amityville Horror (2005).

Nichols' first starring film role was in the horror–thriller P2 (2007). She had a supporting role in the coming-of-age film The Sisterhood of the Traveling Pants 2 (2008) and appeared in Star Trek (2009). She starred in the action film G.I. Joe: The Rise of Cobra (2009) and the sword and sorcery film Conan the Barbarian (2011). She currently plays the lead role of Kiera Cameron in the science fiction television series Continuum.