(also W. Janszoon, W. Janssen). Dates of birth and death unknown. Early 17th-century Dutch navigator and admiral.
Jansz was in the service of the Dutch East India Company. He was the first European to reach the shores of Australia. Sailing aboard the Duyfken, in 1606 Jansz reached the western coast of the Cape York Peninsula, which he thought was part of the island of New Guinea.