What is the relationship between GATT and WTO?

The GATT is the General Agreement on Tariffs and Trade. The WTO is the World Trade Organization. GATT was an international treaty with a temporary international existence, whereas the World Trade Organization is a permanent body whose authority has been ratified by its many member nations. GATT dispute settlement was generally slower and less effective than dispute settlement under the WTO.

What are the principles of GATT?

GATT international trade principles are numerous but it's especially well-known for its “most-favored nation” policy. Basically, countries must treat each trading partner as they would their “most favored nation.” The General Agreement on Tariffs and Trade also put a premium on reciprocity and transparency, as well as the elimination of tariffs and other trade barriers.