Monitoring the Future (MTF) is a long-term study of American adolescents, college students, and adult high school graduates through age 55. It has been conducted annually by the University of Michigan's Institute for Social Research since its inception in 1975 and is supported under a series of investigator-initiated, competitive research grants from the National Institute on Drug Abuse. The 2015 MTF survey involved about 44,900 8th-, 10th-, and 12th-grade students in 382 secondary schools nationwide. The first published results are presented in this report. The report begins with a synopsis of the design and methods used in the study and an overview of the key results from the 2015 survey. This is followed by a separate section for each individual drug class, providing figures that show trends in the overall proportions of students at each grade level (1) using the drug; (2) seeing a "great risk" associated with its use (perceived risk); (3) disapproving of its use (disapproval); and (4) saying that it would be fairly or very easy to get if they wanted to (perceived availability). For 12th graders, annual data are available since 1975 and for 8th and 10th graders since 1991, the first year they were included in the study.