The Indiana State Fair is an annual state fair that spans 18 days in July and August in Indianapolis, Indiana, U.S. The Indiana State Fair debuted in 1852 at Military Park in Indianapolis and is the sixth oldest state fair in the U.S. It is the largest event in the state, drawing between 730,000 and 980,000 visitors annually since 2010. In 2015, readers of USA Today ranked the Indiana State Fair among the ten best state fairs in the country.

A state fair is an annual competitive and recreational gathering of a U.S. state's population, usually held in late summer or early fall. It is a larger version of a county fair, often including only exhibits or competitors that have won in their categories at the more-local county fairs.