Willie Smits, Dutch microbiologist and engineer
Willie Smits (born February 22, 1957, in Weurt, Gelderland, the Netherlands) is a trained forester, a microbiologist, conservationist, animal rights activist, wilderness engineer and social entrepreneur. He has lived in Indonesia since 1985 and is an Indonesian citizen. He is married to Adrienne C. Watson since March 2016.

While working as a forest researcher in East Kalimantan, Indonesia in 1989, Smits encountered a baby orangutan in a cage in a market, and later returned to find it abandoned on a rubbish heap. This was a turning-point in his career: taking the orangutan home, he nurtured it back to health. He was soon given other orangutans to look after, and the work of rescuing, rehabilitating and releasing orangutans into the wild developed into what was to become the Borneo Orangutan Survival Foundation. For over twenty years Smits has worked for the survival of this threatened species of ape, during which time his work has also broadened out into the related areas of sustainable farming, reforestation and remote monitoring of forests. He travels widely, raising awareness of the issues surrounding deforestation in Borneo and the plight of the orangutan, also showing how it has been possible on a relatively small scale to reverse the great damage that is being done to the orangutan and its environment. He became a senior advisor to the Ministry of Forests in Indonesia and has been knighted in the Netherlands.