Most commonly, it refers to the World Trade Organization.

Also formerly, Warsaw Treaty Organization, more usually known as the Warsaw Pact.

write-to-operator, a macro used in computer programming.

World Toilet Organization

The three letter acronym WTO has several meanings.

William Tell Overture

Formerly, the World Tourism Organization, which is now officially abbreviated as UNWTO.

WTO is additionally the acronym of a fictional organization, also called the World Trade Organization, in the video game Deus Ex: Invisible War.

a song by the California punk group Pennywise, which appeared on their sixth album Land of the Free?.