Saturday (2005) is a novel by Ian McEwan set in Fitzrovia, London, on Saturday, 15 February 2003, as a large demonstration is taking place against the United States' 2003 invasion of Iraq. The protagonist, Henry Perowne, a 48-year-old neurosurgeon, has planned a series of chores and pleasures culminating in a family dinner in the evening. As he goes about his day, he ponders the meaning of the protest and the problems that inspired it; however, the day is disrupted by an encounter with a violent, troubled man.

To understand his character's world-view, McEwan spent time with a neurosurgeon. The novel explores one's engagement with the modern world and the meaning of existence in it. The main character, though outwardly successful, still struggles to understand meaning in his life, exploring personal satisfaction in the post-modern, developed world. Though intelligent and well read, Perowne feels he has little influence over political events.

The book, published in February 2005 by Jonathan Cape in the United Kingdom and in April in the United States, was critically and commercially successful. Critics noted McEwan's elegant prose, careful dissection of daily life, and interwoven themes. It won the 2005 James Tait Black Memorial Prize for fiction. It has been translated into eight languages.