Legacy preference or legacy admission is a preference given by an institution or organization to certain applicants on the basis of their familial relationship to alumni of that institution. It is most controversial in college admissions, where students so admitted are referred to as legacies or legacy students. This form of nepotism is particularly widespread in the college admissions in the United States; almost three-quarters of research universities and nearly all liberal arts colleges grant legacy preferences in admissions.

Schools vary in how broadly they extend legacy preferences, with some schools granting this favor only to children of undergraduate alumni, while other schools extend the favor to extended family, including: children, grandchildren, siblings, nephews, and nieces of alumni of undergraduate and graduate programs. A 2005 analysis of 180,000 student records obtained from nineteen selective colleges and universities found that, within a set range of SAT scores, being a legacy raised an applicant's chances of admission by 19.7 percentage points.

Legacy preferences are controversial, as the legacy students tend to be less qualified and less racially diverse than non-legacy students. Legacy students also derive less value from attending a prestigious university. However, legacy students are economically beneficial to universities, as they are perceived to be more likely to donate to their university after graduation and have parents who are perceived to be more generous donors. Legacy preferences are particularly prevalent at Ivy League universities and other selective private universities in the United States.

In the United States, legacy admissions in universities date back to the 1920s. Elite schools used legacy admissions to maintain spots for White Anglo-Saxon Protestants amid fears that Jews, Catholics and Asians were increasingly taking spots at the schools.

A 1992 survey found that of the top seventy-five universities in the U.S. News & World Report rankings, only one (the California Institute of Technology) had no legacy preferences at all; the Massachusetts Institute of Technology also affirmed that it does not practice legacy admissions. Legacy preferences were almost ubiquitous among the one hundred top-ranked liberal arts colleges as well. The only liberal arts college in the top one hundred that explicitly said it did not use legacy preferences was Berea.

Beginning in the 2010s, several top schools ended legacy preferences, including Johns Hopkins University in 2014, Pomona College in 2017, Amherst College in 2021, and Wesleyan University in 2023. By 2024, four states (Colorado, Maryland, Virginia, and California) had banned legacy admissions at universities.

In 2023, the bipartisan Merit-based Educational Reforms and Institutional Transparency Act was proposed in the U.S. Congress to ban legacy preferences.

Currently, the Ivy League institutions are estimated to admit 10% to 15% of each entering class using legacy admissions. For example, in the 2008 entering undergraduate class, the University of Pennsylvania admitted 41.7% of legacies who applied during the early decision admissions round and 33.9% of legacies who applied during the regular admissions cycle, versus 29.3% of all students who applied during the early decision admissions round and 16.4% of all who applied during the regular cycle. In 2009, Princeton admitted 41.7% of legacy applicants—more than 4.5 times the 9.2% rate of non-legacies. Similarly, in 2006, Brown University admitted 33.5% of alumni children, significantly higher than the 13.8% overall admissions rate. In short, Ivy League and other top schools typically admit legacies at two to five times their overall admission rates. Among top universities, the University of Notre Dame and Georgetown University are known to weigh legacy status heavily in their application processes.