Doctoral funding in the United States rarely comes from a single source. Most PhD students are supported through some combination of a funded admission offer from their institution, a federal individual fellowship they apply for separately, and, less commonly, a private foundation award. Understanding how these three layers relate to one another matters for research administrators advising prospective students, for graduate program coordinators building offer packages, and for sponsored-programs staff who need to know which funding is institutionally administered versus individually held by the student.
This guide is a structural overview of the doctoral funding landscape, not a searchable database of every fellowship. For specific program pages, see the linked terms and guides throughout.
The three layers of doctoral funding
It helps to think of doctoral funding as three distinct layers, each with a different funding relationship, a different applicant, and a different administrative home:
- Institutional funding — assistantships and fellowships built into the admission offer, funded and administered by the graduate program or department.
- Federal fellowship programs — competitive awards the student applies for as an individual, funded by a federal agency and held directly by the student rather than paid through a PI’s grant.
- Private foundation fellowships — a smaller, more field-specific layer of individually held awards from non-governmental funders.
A student can hold funding from more than one layer at once (for example, a department-funded teaching assistantship in year one, followed by an NSF GRFP or NIH F31 for the following years), and institutions vary widely in how they coordinate stipend levels, tuition remission, and health insurance across layers when a student’s federal or foundation award doesn’t cover everything the institutional package did.
Institutional funding: assistantships and fellowships built into admission
For most PhD students, the first and largest source of support is the funding package offered by the admitting institution or department. This typically takes one of three forms, often combined across years of study:
- Research assistantship (RA) — the student is paid to work on a faculty member’s funded research project, usually the project that will become their dissertation. RA funding is drawn from the supervising investigator’s grant or contract and is therefore contingent on that funding continuing.
- Teaching assistantship (TA) — the student is paid by the department, typically from state appropriations or tuition revenue, in exchange for teaching or grading duties. TA funding is generally more stable than RA funding because it isn’t tied to a specific grant’s lifecycle, but it comes with a teaching-time commitment that competes with dissertation research.
- Institutional or departmental fellowship — a no-strings, department- or university-funded stipend, often used in a student’s first year (before they’ve joined a lab or begun teaching) or as a competitive top-up awarded to incoming students the program wants to recruit.
Institutional packages typically bundle a stipend with a tuition waiver and, at many US institutions, subsidized health insurance. Because this funding is administered internally, the department or graduate school — not the federal government or an outside foundation — sets the stipend level, and levels vary substantially by institution, field, and cost of living. Where a training program spans a cohort of students in a research area, institutions may hold an NIH T32 institutional training grant, a related but distinct mechanism from an individually held fellowship: the department receives the grant and selects trainees to fill designated slots, rather than the student competing individually for the award. See T32 (NIH Institutional Research Training Grant) for how that mechanism differs from the individual F-series fellowships below.
Federal fellowship programs: individually held, portable awards
The second layer is federal fellowships that a doctoral student applies for directly, independent of their institution’s own funding decision. These are individually held awards — the funding relationship is between the agency and the student (with a faculty sponsor or mentor, in most cases), not between the agency and the institution. That distinction matters administratively: an individual fellowship is typically portable if the student changes institutions, and it displaces rather than stacks on top of institutional RA/TA funding for the years it covers.
The major US federal predoctoral mechanisms, by agency:
NSF Graduate Research Fellowship Program (GRFP)
The National Science Foundation’s GRFP is the largest and most widely known federal fellowship for early-stage graduate students in NSF-supported STEM and STEM-education fields. It funds three years of support across a five-year eligibility window, paid as a stipend to the fellow plus a separate Cost of Education allowance paid to the institution. Eligibility is restricted to US citizens, nationals, and permanent residents, and applicants must be in the early stages of their graduate study — those who have completed more than one academic year in their current program at the time of application are generally not eligible, aside from a narrow return-to-study exception. See NSF GRFP (Graduate Research Fellowship Program) for the full eligibility and application structure.
NIH F31 — Predoctoral Individual NRSA Fellowship
The Ruth L. Kirschstein National Research Service Award (NRSA) Individual Predoctoral Fellowship, known by its F31 activity code, supports doctoral students in biomedical, behavioral, and clinical science PhD (or equivalent) programs who have reached the dissertation-research stage. Unlike GRFP, the F31 applicant is the student themselves, applying with a named faculty sponsor, and the award is specific to the dissertation research project described in the application — it is not a general graduate-school-entry fellowship. Stipend levels follow the NIH’s published NRSA stipend scale (see NRSA Stipend Levels), and the mechanism is distinct from the NIH F32, which funds postdoctoral rather than predoctoral trainees (compare in F31 vs. F32). Full detail at F31 (NIH Predoctoral Individual NRSA Fellowship).
DOE Computational Science Graduate Fellowship (CSGF)
The Department of Energy’s Computational Science Graduate Fellowship supports PhD students whose research applies high-performance computing to problems in science or engineering. Administered on DOE’s behalf by the Krell Institute, the CSGF provides an annual stipend, full payment of university tuition and required fees, and an academic allowance, renewable for up to four years; fellows also complete a required practicum of roughly three months at one of the DOE national laboratories. It is narrower in scope than GRFP or F31 — restricted to computational-science applications rather than open across STEM or biomedical fields generally — which makes it a useful example of how federal fellowship programs cluster around an agency’s own mission rather than forming one unified national doctoral-funding system.
Other federal mechanisms
Beyond these three, agencies including the Department of Defense (National Defense Science and Engineering Graduate Fellowship), NASA, and EPA run their own smaller predoctoral fellowship competitions, generally following the same individually-held, agency-mission-restricted pattern as CSGF. Research administrators advising students across disciplines should expect to check the specific agency whose mission best matches the dissertation topic, rather than assuming one program covers all fields.
Private foundation fellowships
The third, smaller layer is private foundation and non-profit fellowships. These are typically field- or mission-specific, more variable in structure than federal programs, and often intended to supplement rather than fully replace institutional or federal funding — some are one-year, terminal-project awards (for example, dissertation-completion fellowships aimed at students in their final writing year) rather than multi-year support spanning the whole doctorate. Compared with the federal programs above, foundation fellowships are far more numerous individually but each covers a much narrower population, which is why this guide treats them as a category rather than listing individual programs — a research administrator’s field, institution, and student population determine which foundation programs are actually relevant, and that varies too widely to generalize.
How the layers interact
A few structural points matter for anyone administering or advising on doctoral funding:
- Federal and foundation fellowships typically displace, not stack on, institutional RA/TA funding for the years they cover — a student who wins an NSF GRFP generally stops being paid as a TA or RA for those three years, freeing the department’s RA/TA funding for another student, though practice varies by institution.
- Institutions may still need to supplement when an external fellowship’s stipend or the Cost of Education allowance doesn’t fully cover the institution’s own tuition and fees or standard stipend level — a common source of negotiation between graduate schools and departments.
- Award timing rarely aligns. Institutional admission offers are typically made in the spring before enrollment; GRFP and F31 results come later (F31 review cycles run on the NIH’s standard cycle; GRFP announces in the spring following a fall application). This means most students start on institutional funding and, if successful, transition onto a federal fellowship in a later year rather than beginning their doctorate already holding one.
- Eligibility windows are typically early-career-specific. Both GRFP and F31 restrict eligibility to students who have not progressed too far into their program (GRFP) or who have reached the dissertation stage (F31) — administrators should not assume a program is available at any point in a student’s doctorate.
Frequently asked questions
What is the difference between an assistantship and a fellowship?
An assistantship (research or teaching) requires the student to work — conducting research for a PI’s grant or teaching/grading for a department — in exchange for a stipend and, typically, tuition remission. A fellowship, whether institutional, federal, or foundation-funded, generally does not carry a work requirement in exchange for the stipend; the student’s obligation is to make progress on their own dissertation research.
Can a doctoral student hold institutional and federal funding at the same time?
Generally no, for the same period — federal individual fellowships like GRFP and F31 typically become the student’s primary funding source for the years they’re active, replacing rather than supplementing an RA or TA position, though the specific arrangement is negotiated between the student, department, and graduate school.
Is a T32 the same kind of award as an F31?
No. A T32 is an institutional training grant — the institution applies for and holds the award, and the department selects trainees to fill funded slots within it. An F31 is applied for and held by the individual student. Both are NIH National Research Service Award (NRSA) mechanisms and both fund predoctoral training, but the funding relationship (institution-held versus individually-held) is different. See T32 (NIH Institutional Research Training Grant).
Do federal doctoral fellowships require US citizenship?
Requirements vary by program. NSF GRFP and NIH F31 both restrict eligibility to US citizens, nationals, or permanent residents. Agency-specific and foundation programs should be checked individually, since eligibility rules are not standardized across funders.
Where does DOE CSGF funding differ from NSF GRFP?
CSGF is restricted to PhD students applying high-performance computing to science or engineering problems and includes a required practicum at a DOE national laboratory; GRFP is open across a broader range of NSF-supported STEM and STEM-education fields and carries no practicum requirement. Both are individually held, multi-year federal fellowships administered on a national competition basis.
