The Duke of Teck was a title in the British peerage, created in 1900 for Prince Alexander of Teck. He was born in 1866 and was a member of the German nobility, being the son of Prince Francis of Teck and Princess Mary Adelaide of Cambridge. The title was associated with the town of Teck in Germany. The Duke of Teck was known for his close ties to the British royal family, particularly through his marriage to Princess Mary of Teck, who later became Queen Mary. The title became extinct upon his death in 1912, as he had no male heirs.