ACT, abbreviation for American College Testing, is a test published by American College Testing to measure a student's ability in math, verbal comprehension and problem solving. Usually students take this test during their junior or senior year of high school in place of, or in addition to, the SAT for entrance into college. The exam is offered six times a year, in February, April, June, September, October, and December. It is more widely used in the Midwest region of the US. It covers English, reading, science, and math. These subject test scores can be used in lieu of SAT II subject tests, which are required for admission to some of the more competitive colleges.

The ACT emerged in 1959 as a competitor to the College Board's Scholastic Aptitude Test (now SAT). Versus the SAT, the ACT is oriented more towards knowledge content (facts), rather than vocabulary and analogies.

An alternative to the SAT, this test has gained wide acceptance by a broad range of institutions in recent years and is given during the school year at test centers. The score is the average of all four tests; the average score is around 20 to 21; the maximum score is 36.