Sophia Dorothea of Brunswick-Lüneburg-Celle (15 September 1666 – 13 November 1726) was the repudiated wife of future King George I of Great Britain, and mother of George II.
The union with her first cousin was an arranged marriage of state, instigated by the machinations of his mother, Electress Sophia of Hanover.
She is best remembered for her alleged affair with Philip Christoph von Königsmarck that led to her being imprisoned in the Castle of Ahlden for the last thirty years of her life.