Johns Hopkins University is a private research university in Baltimore, Maryland, United States. It opened in February 1876, financed by a bequest of about $7 million from the Baltimore merchant and Quaker philanthropist Johns Hopkins, whose unusual first name came from a family surname. Its trustees deliberately broke with the teaching-centred colleges of the period, adapting the German Humboldtian model in which advanced instruction and original inquiry are treated as inseparable. Under Daniel Coit Gilman, its first president, the institution recruited working scholars and built graduate programmes and laboratories around them. It is generally identified as the first research university in the United States.

The university is organised into nine academic divisions spread across several sites. Homewood, in northern Baltimore, holds the Zanvyl Krieger School of Arts and Sciences and the Whiting School of Engineering, and accommodates most undergraduate study. The East Baltimore medical campus contains the School of Medicine, the School of Nursing and the Bloomberg School of Public Health, established in 1916 as the earliest school of its kind. The Peabody Institute, an 1857 conservatory, joined as a division in 1977; the Carey Business School sits in Harbor East; and the School of Advanced International Studies works from the Hopkins Bloomberg Center in Washington, D.C., with further sites in Bologna and Nanjing.

Research activity is unusually concentrated. Johns Hopkins has drawn more federal research funding than any other American university every year since 1979, and its annual research expenditure approached $3.1 billion in fiscal 2020. Those totals include the Applied Physics Laboratory at Laurel, Maryland, a government-facing centre whose spacecraft have flown to Mercury and Pluto. Thirty-four Nobel laureates have been affiliated with the institution as students, faculty or researchers. Enrolment in the autumn of 2024 reached 30,210, of whom 6,356 were undergraduates, leaving a student body weighted heavily towards graduate and professional study; undergraduate admission remains highly selective.