This document provides an overview of the United States Generalized System of Preferences (GSP) program. The GSP program provides preferential duty-free treatment for over 3,400 products from 129 designated beneficiary countries. An additional 1,400 products are eligible only when imported from least developed beneficiary developing countries. This guidebook outlines the countries and products eligible for GSP, how to claim GSP benefits, rules of origin requirements, and procedures for modifying the GSP program.