The University of Delaware (UD) is a privately governed, state-assisted land-grant public research university located in Newark, Delaware, United States. Tracing its origins to 1743 when Presbyterian minister Francis Alison established a 'Free School' in New London, Pennsylvania, the institution evolved through several name and location changes. By 1765, it had moved to Newark and received a charter as the Academy of Newark in 1769 from the colonial Penn government. In 1833, it was rechartered as Delaware College, and in 1921, it was renamed the University of Delaware. It became coeducational in 1945 following a merger with the Women's College of Delaware, ending the prior separation of male and female colleges. UD is classified as an R1 Doctoral University with very high research activity and holds designations as a Land-Grant, Sea-Grant, and Space-Grant institution, reflecting its commitments to agriculture, marine science, and aerospace research.

UD offers a wide array of academic programs across ten colleges and schools, including 4 associate, 163 bachelor's, 136 master's, and 64 doctoral programs. As of fall 2023, it enrolls 24,221 students, making it the largest university in Delaware by enrollment. The main campus is in Newark, with satellite campuses in Dover, Wilmington, Lewes, and Georgetown. The university pioneered the first study abroad program in the United States in 1923, now offering over 80 programs in more than 45 countries. Notable research facilities include the Delaware Biotechnology Institute (established 1999), focused on interdisciplinary life sciences, and the Institute of Energy Conversion (founded 1972), the world's oldest solar energy research institute, which has received significant funding for advanced solar cell development.

UD maintains strong ties to state and federal initiatives, receiving grants such as a $13.1 million award from the Delaware Community Foundation for Alzheimer's prevention research. It supports community services like the University of Delaware Emergency Care Unit (UDECU), a student-run organization providing emergency medical services with an ambulance, response vehicle, and bike team. The university's history includes periods of financial challenges and enrollment fluctuations in its early years, but it has grown into a prominent public research institution with a focus on innovation in biotechnology, energy, and health sciences. Notably, President Joe Biden began his undergraduate studies at the University of Delaware.