Genevieve O'Reilly (born January 6, 1977 in Dublin, Ireland) is an Irish film, television and stage actress who has worked in both the United Kingdom and Australia.

In 2000, she graduated from the National Institute of Dramatic Art (NIDA) in Sydney, Australia with a degree in Performing Arts.

Besides portraying the ionic character Mon Mothma in the prequel Star Wars: Episode III - Revenge of the Sith (for which most of her speaking lines were cut for time), O'Reilly also portrayed Officer Wirtz in the sequels The Matrix Reloaded and The Matrix Revolutions, as well as Princess Diana in the 2007 TV movie Diana: Last Days of a Princess. Her film credits also include Cyber Wars (with David Warner), The Young Victoria, Forget Me Not and 2015's Survivor (with Milla Jovovich).

O'Reilly has also appeared in numerous TV series such as "BeastMaster", "Young Lions", "All Saints", "The State Within" (with Jason Isaacs), "The Time of Your Life", "Spooks" (with William Hope), "New Tricks", "Law & Order: UK", "Waking the Dead", "Episodes", "Midsomer Murders", "The Last Weekend" and "Crossing Lines".

Theatrically, O'Reilly has performed such stage roles as Olivia in Twelfth Night, Veronica in The Ugly Man, Millamant in The Way of the World, Ruth in Così, Queen Isabel in Richard II, Valerie in The Weir, Isabelle in Birdsong, Helena in Emperor and Galilean, Jennifer in The Doctor's Dilemma and many more.