Jonkheer Jan Willem Janssens GCMWO was a Dutch nobleman, soldier and statesman who served both as the governor of the Dutch Cape Colony and governor-general of the Dutch East Indies.

The Dutch Cape Colony was a Dutch United East India Company (VOC) colony in Southern Africa, centered on the Cape of Good Hope, from where it derived its name. The original colony and the successive states that the colony was incorporated into occupied much of modern South Africa. Between 1652 and 1691, it was a Commandment, and between 1691 and 1795, a Governorate of the VOC. Jan van Riebeeck established the colony as a re-supply and layover port for vessels of the VOC trading with Asia. The Cape came under VOC rule from 1652 to 1795 and from 1803 to 1806 was ruled by the Batavian Republic. Much to the dismay of the shareholders of the VOC, who focused primarily on making profits from the Asian trade, the colony rapidly expanded into a settler colony in the years after its founding.