The Orion Publishing Group was founded in 1991. Soon after, Orion began negotiations with Lord Weidenfeld, and acquired Weidenfeld & Nicolson as the nucleus of the new publishing group; Lord Weidenfeld remained as chairman of W&N, a post he still occupies.

Weidenfeld & Nicolson, founded in 1949, was an established name with a history of quality publishing. Its imprints include Everyman Paperbacks.

Orion Books was launched in 1992, and in 1993 Orion bought the assets of Chapman Publishers, a small general publishing house. That year it also acquired a warehousing and distribution centre, Littlehampton Book Services (LBS) based in Sussex.

In December 1998, Hachette acquired the publishing house Cassell & Co, whose imprints included Victor Gollancz Ltd, which became part of the Orion Group. Gollancz had been founded in 1928 and had continued as an independent publisher until 1989, when the last family member retired and the business was sold. Out of this acquisition, Orion also took ownership of the Cassell Military list.

Also in 1998, a majority of the share capital of the Orion Publishing Group was sold to Hachette Livre, the publishing arm of the French Lagardère Group. In 2003 Hachette Livre became the sole owner of the group. In 2004, Hachette also acquired the Hodder Headline Group, and Hachette UK was formed, with Orion as its largest single component.