Division I (D-I) is the highest level of intercollegiate athletics sanctioned by the National Collegiate Athletic Association (NCAA) in the United States.
D-I schools include the major collegiate athletic powers, with larger budgets, more elaborate facilities, and more athletic scholarships than Divisions II and III as well as many smaller schools committed to the highest level of intercollegiate competition. This level was once called the University Division of the NCAA, in contrast to the College Division; this terminology was replaced with numeric divisions (I, II, III) in 1973. In football only, Division I was further subdivided in 1978 into Division I-A (the principal football schools) and Division I-AA;. Currently, Division I is divided among "Football Bowl Subdivision" (FBS) schools, "Football Championship Subdivision" (FCS) schools, and "Non-Football" schools. For the 2012-13 school year, Division I contains 340 of the NCAA's 1,066 member institutions, with 120 in FBS, 122 in FCS, and 98 in NFS. There was a moratorium on any additional movement up to D-I until 2012, after which any school desirous of moving to D-I must first be accepted for membership by a conference and must show the NCAA that it has the financial ability to support a D-I program.

All D-I schools must field teams in at least seven sports for men and seven for women or six for men and eight for women, with at least two team sports for each gender. There are several other NCAA sanctioned minimums and differences that distinguish Division I from Divisions II and III.

In addition to the schools that compete fully as D-I institutions, the NCAA allows D-II and D-III schools to classify one men's and one women's sport (other than football or basketball) as a D-I sport, as long as they had been sponsoring those sports prior to the latest rules change in 2011.