Ephron was born in Beverly Hills, CA to parents Henry and Phoebe Ephron, both East Coast born and raised screenwriters. She is the sister of Nora Ephron and Delia Ephron and Hallie Ephron. Amy Ephron is the author of six novels — her latest, the best seller One Sunday Morning, is out in paperback. Her national bestseller, A Cup of Tea, spent 37 weeks on the LA Times bestsellers list and has been bought by film producer Jerry Bruckheimer. A Cup of Tea won Ephron the 2005 Southern California Booksellers Association award for fiction, received the Booklist Best Fiction of the Year 2005 award and was a Barnes and Noble Book Club selection.

Ephron is a frequent contributor to Harper's Bazaar, Vogue, ELLE, LA Times, Saveur, National Lampoon, The Realist, LA Weekly, LA Style, and The Huffington Post. As a film executive she worked on A Little Princess, Born on the Fourth of July and Out of Africa. She also runs her own food website called One for the Table, which publishes articles and recipes about food, love, and politics.

She has been married twice, first to film producer Sasha Harari, with whom she has three children, Anna, Maia and Ethan, and currently to lawyer Alan Rader.