Willem Johannes Leyds was a Dutch lawyer and statesman who served as state attorney and state secretary of the South African Republic. From 1898 to 1902, during the crucial period of the Second Boer War, he was the Republic's special envoy and minister plenipotentiary in Brussels, accredited to several European states.

The South African Republic, also known as the Transvaal Republic, was an independent Boer republic in Southern Africa which existed from 1852 to 1902, when it was annexed into the British Empire as a result of the Second Boer War.