Marsha Thomason is an English actress, who is best known in the U.S. for playing Nessa Holt in the first two seasons of NBC's series Las Vegas, and for her recurring role on ABC's Lost as Naomi Dorrit.

Thomason was born to an English father, Peter Thomason (aka Thomo), and a Jamaican mother. She attended Holy Trinity Primary School in Blackley, then went onto North Manchester High School for Girls, before attending Oldham Sixth Form College to study for A levels in Media Studies, Theatre Studies and Performing Arts. Thomason attended the Manchester Metropolitan University to study a BA in English.

Thomason first came to prominence on British television in the series Playing the Field and Where The HeartIs, as well as in the first series of the BBC Three drama Burn It. In the U.S., she also acted in Disney's The Haunted Mansion, playing Eddie Murphy's wife, she played Brandyin the movie My Baby's Daddy, and played Victoria in Black Knight. She also played the character Vicki in Pure. Marsha starred on the US television series Las Vegas as Nessa Holt in seasons 1 and 2, a total of 47 episodes.

On 21 October 2004 she was a guest on the radio show Love Line. In January 2008, she appeared in Messiah V: The Rapture, alongside Marc Warren. In August 2008, Thomason was cast as a series regular in the CW's new show Easy Money.

Most recently, Thomason was a recurring character on the television show Lost as Naomi Dorrit. Being a friend of Dominic Monaghan's (who played Charlie Pace on the series), she was a huge fan of the show and excited to be cast.

She first appeared in the third season episode "Catch-22," which aired on April 18, 2007, and continued to appear in all the remaining episodes of the season. The character was knifed in the back in the third season's finale and succumbed to her injuries in the first episode of season 4.