Cashew is native to northeastern Brazil, in the area between the Atlantic rain forest and the Amazon rainforest.

Cashew is sometimes referred to as a rainforest species and the nuts are found in products that have a rainforest friendly label or connotation.

The Portuguese introduced cashew to the west coast of India and east Africa in the 16th century, shortly after its discovery in 1578. It was planted in India initially to reduce erosion. The trees were well adapted to the region, and became naturalized. Trees also became naturalized in Central America and the Caribbean islands. Nut domestication predated the arrival of Europeans to Brazil. Native South Americans discovered that roasting nuts in fire would remove the caustic oil, allowing the nut to be cracked and consumed without any ill effects.