Division I is the highest level of intercollegiate athletics sanctioned by the National Collegiate Athletic Association in the United States. "D-1" schools are the major collegiate athletic powers, with larger budgets, more elaborate facilities, and higher numbers of athletic scholarships. This level was once called the "University" division of the NCAA in contrast to the "College" division; this terminology was replaced with the current numeric (I, II, III) divisions in 1973. In football only, Division I was further subdivided into Division I-A (the principal football schools) and Division I-AA in 1978. Subsequently the term "Division I-AAA" was added to delineate Division I schools which do not field a football program at all.

The most important differences between Division I-A and Division I-AA are:

• Championships

Division I-A football is the only NCAA-sponsored sport without an organized tournament to determine its champion. See Bowl Championship Series for more details on the current system.

Division I-AA determines its champion in a 16-team single-elimination tournament.

• Scholarships:

Division I-A schools are currently limited to a total of 85 players receiving financial assistance. For competitive reasons, and due to the fact that a student on partial scholarship counts fully against the total of 85, virtually all I-A schools that are not on NCAA probation give 85 full scholarships. The service academies—in this context, Army, Navy, and Air Force—are exempt from this rule, as all of their students receive full scholarships from the federal government.

Division I-AA schools are currently restricted to giving financial assistance amounting to 65 full scholarships. Unlike I-A schools, I-AA schools may freely give partial scholarships; they have no limit as to the number of players receiving assistance. However, competitive forces mean that a substantial number of players in I-AA programs are on full scholarships.

A current controversy in the NCAA is over whether schools will continue to be allowed to have one showcased program in Division I with the remainder of the athletic program in a lower division, as is the case of, notably, Johns Hopkins University in lacrosse. This is an especially important issue in hockey, where several Division II and Division III athletic programs compete in Division I in that sport.