The Rosie Effect is a 2014 novel by Australian novelist Graeme Simsion and the second book of a trilogy including the previous instalment, The Rosie Project, and its sequel, The Rosie Result. The work was first published on 24 September 2014 in Australia / New Zealand by Text Publishing and the rights have since been sold in 24 other territories. International sales are more than 1 million copies. In the United States the novel was published through Simon & Schuster and in the United Kingdom through Penguin Books. The novel centres on Don Tillman, a socially awkward genetics professor, and his preparation for fatherhood.

Graeme C. Simsion is a New Zealand-born Australian author, screenwriter, playwright, and data modeller, best known for his first novel The Rosie Project.