Ursula Martinez is a London-based Anglo-Spanish performance artist noted for her use of nudity and non-actors.

Her father is British and her mother Spanish. She has worked with experimental theater groups Forced Entertainment, Insomniac Productions, The Glee Club, and Duckie. In the 1990s she began to combine this with her experience in cabaret, establishing a reputation in the queer arts community. With collaborator Mark Whitelaw, she created A Family Outing, a performance piece in which she deconstructed her own childhood and coming out, including appearing nude on stage alongside both her parents. It debuted at the 1998 Edinburgh Festival and toured for three years. The Independent said of it that she had "created a new theatrical genre".

She and Whitelaw next created a piece called Show Off, which also toured internationally. The second performer in this piece is her ex-love Carmen Cuenca, which is made known to the audience as part of the performance. Their third collaboration is OAP (Old Age Pensioner), which opened at The Barbican in October 2006. Together, the three pieces constitute a trilogy "exploring self-obsession, identity and the artifice of performance".

Martinez has also created a number of shorter works solo, including Curing Homosexuality, The Class Club, C'est Vauxhall!!, and C’est Barbican, which won an Olivier Award. Her short films include Oh Baby (a runner-up for the 1997 Dick Award) and Venkel's Syndrome, winner of the Silver Spike Award at the 2001 Valladolid International Film Festival. Her short piece Hanky Panky, combines a handkerchief trick magic act with striptease and was filmed at the Just for Laughs comedy festival in Montreal, has been widely circulated on the internet.