Stephen Leacock Associates was founded in 1946 by a number of Stephen Leacock's friends to perpetuate his memory.  The Associates began awarding the Leacock Medal for Humour in 1947.  The number of entries has continually grown — 84 books were put forward by publishers and writers for 2020, the most ever.  An anonymous panel of judges, appointed from across Canada by the Leacock Associates’ Board of Directors, vets all entries and selects the long and short lists and the final winner.

Previously, the shortlist of five books was typically announced on April 1st, the winning book announced at the end of April at a luncheon, and the Leacock Memorial medal and a cash award presented to the winner in June at the Leacock gala dinner at Geneva Park Conference Centre in Orillia, Ontario.

In 2015, the Leacock Associates added a long list announcement of the top ten books.

In 2016, the announcement format evolved again into its  present form:

• Leacock Medal submissions are received from August 1 until December 31
• The long list of ten finalists is announced to the public in April
• The shortlist of just three finalists is announced in early May
• The winner is announced (and the prizes and Medal awarded) at a June Gala Dinner as part of a Gala Weekend honouring the Medal finalists and the Student Prize finalists
• The Gala Weekend is open to the public and media