Below, you'll find a fairly comprehensive list of the major scholarships available to undergraduates, graduating seniors, and graduate students. These are divided by category and link to their official websites.
British and Irish graduate scholarships (begin working with scholarships office in the spring)
Churchill Scholarship (Cambridge University)
Gates Cambridge Scholarship (Cambridge University)
Marshall Scholarship (United Kingdom)
Mitchell Scholarship (Ireland and Northern Ireland)
National Institutes of Health (Oxford and Cambridge)
Rhodes Scholarship (Oxford University)
Clarendon Fund (Oxford University)
Ertegun Fellowship (Oxford University, humanities)
Weidenfeld-Hoffmann Scholarship (Oxford University)
Other university-wide scholarships at Oxford
Saltire Scholarship (Scotland)
Other graduate scholarships
DAAD Scholarship in Germany (undergrad and grad)
Fulbright Scholarship
James Madison Graduate Fellowships (teaching U.S. Constitution and history)
Knight-Hennessy Scholarship, graduate fellowship at Stanford University
Phi Kappa Phi Graduate Fellowship
Schwarzman Scholars, one-year graduate fellowship to China
Environmental and Native American-focused scholarships
Morris K. Udall Scholarship (second- and third-year undergraduates)
NSF - Clean Energy Grants
Sustainable Agriculture Scholarship
Doris Duke Conservation Fellows Program (grad students in conservation)
Brower Youth Awards (Earth Island Institute)
Eckenfelder Scholarship
Garden Club of America Scholarship
National Environmental Health Association
Middlebury Fellowship in Environmental Journalism
Wells Fargo Scholars (American Indian/Alaska Native students pursuing business)
European Union scholarships
Erasmus Mundus (fully funded master’s programs that place you in several EU countries over two years)
Minority scholarships
Humanity in Action
LGBTQ Students & College Affordability
Minority Scholarships
Point Foundation Scholarship
Military scholarships
Pat Tillman Foundation Leadership through Action
New Americans scholarships
Merage Foundation American Dream Fellowship (funding suspended)
Soros Fellowship for New Americans
Public service, policy & leadership scholarships
Carnegie Endowment Junior Fellows Research Assistantships
Harriman Foreign Service Fellowship (State Department internships)
Humanity in Action
Pickering Foreign Affairs Fellowship
Public Policy & International Affairs Fellowship Program
Charles B. Rangel International Affairs Scholarship
Scoville Peace Fellowship in Washington
Harry S. Truman Foundation Scholarship (third-year undergraduates)
Scientific research, mathematics & medical school scholarships
Barry Goldwater Scholarship (second- and third-year undergraduates)
Department of Energy Science Office Graduate Fellowship
Hertz Foundation Scholarship (hard sciences)
Howard Hughes Medical Institute Predoctoral Fellowships
National Health Service Corp Medical Scholarship
National Institutes of Health – Graduate Partnership Program
National Institutes of Health – MD/PhD
National Institutes of Health - Oxford and Cambridge
National Institutes of Health - Undergraduate Research Scholarship Program
National Institutes of Health Post-Baccalaureate IRTA Program
National Science Foundation Graduate Research Fellowship (Enter “Graduate Research Fellowship” in the search field.) Deadline is early November
National Defense Science & Engineering Graduate Fellowships
Tylenol Scholarship - medical-related career focus (undergrads)
Travel-study scholarships
American-Scandinavian Foundation Fellowship
American University in Cairo Presidential Internship
Boren Scholarship/Fellowship (National Security Education Program)
Chinese Scholarship Council (post-graduate, 2-7 years of funding)
DAAD Scholarship in Germany (undergrad and grad)
Fulbright Scholarship
German Chancellor Fellowships
Gilman International Scholarship Program (undergraduate)
Humanity in Action
Indicorps
Princeton in Africa, Princeton in Asia, Princeton in Latin America
Rotary Peace Fellowship
Schwarzman Scholarship (China)