Established in London in 1985, by an American expatriate, Michael O'Mara, a native of Philadelphia, Pennsylvania, and his British wife, Lesley, the company focuses on non-fiction books from autobiographies and memoir to colouring.

One of the publishing house's most influential publications was Diana: Her True Story by Andrew Morton, the second highest-selling authored work in the UK in the 1990s.

O'Mara Books has a reputation for publishing autobiographies and biographies, with a list that includes Roger Moore, Craig Revel Horwood, Michelle Heaton, Meghan Markle, José Mourinho, Billie Eilish and Harry Styles.

In 2021 they launched the Buster Wellbeing Books with Feeling Good About Me written by Ellen Bailey and Lesley Pemberton, with the aim to bring mindfulness to children.

Its notable authors and illustrators include Kerby Rosanes, Lulu Mayo, Emma Mitchell, Meera Lee Patel and Andrea Zanatelli.