4-H is a U.S.-based network of youth organizations whose mission is "engaging youth to reach their fullest potential while advancing the field of youth development". Its name is a reference to the occurrence of the initial letter H four times in the organization's original motto "head, heart, hands, and health", which was later incorporated into the fuller pledge officially adopted in 1927. In the United States, the organization is administered by the National Institute of Food and Agriculture of the United States Department of Agriculture (USDA). 4-H Canada is an independent non-profit organization overseeing the operation of branches throughout Canada. There are 4-H organizations in over 50 countries; the organization and administration varies from country to country.

The goal of 4-H is to develop citizenship, leadership, responsibility and life skills of youth through experiential learning programs and a positive youth development approach. Though typically thought of as an agriculturally focused organization as a result of its history, 4-H today focuses on citizenship, healthy living, science, engineering, and technology programs. Clubs in today's 4-H world consist of a wide range of options each allowing for personal growth and career success. The 4-H motto is "To make the best better", while its slogan is "Learn by doing" (sometimes written as "Learn to do by doing"). As of 2016, the organization had nearly 6 million active participants and more than 25 million alumni.