Graduate Admissions

HSS welcomes applications from students who are interested in working full time toward a doctor of philosophy degree.

All qualified applicants will be considered for admission to one of HSS's two PhD programs: one in the social sciences, which includes the fields of economics and political science, among others, and the other in behavioral and social neuroscience. Admission to these programs is highly competitive; both programs are deliberately small and selective, with the admissions committee looking for students who demonstrate a commitment to scholarship, a willingness to work hard—as evidenced by letters of recommendation or other achievements—and expressed interests that align with those of the HSS faculty.

General Qualifications

Caltech requires that PhD applicants in any field be able to clearly and forcefully express themselves in written and spoken English. Additionally, each of HSS's PhD programs has its own admissions criteria, which are detailed in the following paragraphs.

Social Sciences PhD

Modern approaches to social science require the ability think abstractly and quantitatively. As such, applicants to the social sciences PhD program must be skilled in formal reasoning. Although the division does not require that an applicant's undergraduate degree be in any of the social sciences, the admissions committee expects every applicant to demonstrate a commitment to social science research. To be prepared to succeed in the social science program, students should have a solid undergraduate background in mathematics, including at least

  • two years of calculus, at the level of Apostol's Calculus, volumes 1 and 2; and  
  • linear algebra, at the level of Apostol's Calculus, volume 2.

It also is highly recommended that applicants complete an introductory course in mathematical statistics and real analysis before entering the HSS programs. 

All applicants to the social sciences PhD program are required to submit Graduate Record Examination (GRE) scores, although the admissions committee does not require GRE subject exams. Most applicants admitted into the HSS graduate programs have exam scores in the top decile. Caltech requires applicants whose first or native language is not English to take a test of English as a Foreign Language (TOEFL) as part of the application procedure.

Behavioral and Social Neuroscience PhD

A prerequisite to entering the behavioral and social neuroscience (BSN) PhD program is a bachelor's degree with an undergraduate major in economics, psychology, neuroscience, biology, physics, mathematics, computer science, or a related discipline. Applicants should have a broad academic foundation that will prepare them to succeed in the advanced courses in computational science, neuroscience, psychology, and economics that are required as part of the BSN program.

All applicants for admission, including those from foreign countries, are also strongly urged to submit Graduate Record Examination (GRE) scores for

  • the verbal and quantitative aptitude tests;
  • a subject test in one of the following areas: physics, biology, engineering, mathematics, or computer science.

Application Deadlines

To be considered for admission, a complete application, including all supporting material (including GRE and TOEFL scores), must be submitted to Caltech no later than December 15. Applicants to the HSS PhD programs are encouraged to submit their applications online through the Graduate Studies Office website.

If you have questions about the application process, please contact the Option Manager.

Financial Aid

Caltech offers competitive stipends in the form of fellowships and research and teaching assistantships, which are designed to cover tuition and living expenses.  Students in good standing generally receive financial support for a maximum of five years. Funding for the summer quarters is not guaranteed, however it may be provided based on the availability of such funding and on an individual student's performance. As a matter of educational policy, graduate students are expected to act as graduate teaching assistants at some point in their career.

Due to the full-time and research-intensive nature of both PhD programs in HSS, many students are also supported with research assistantships. Graduate students in all programs are also encouraged to apply for external fellowships.


For additional information, please visit the following pages:
Social Sciences PhD Program
Behavioral & Social Neuroscience PhD Program
Job Market Candidates
Course Descriptions