The Smithsonian Astrophysical Observatory (SAO) Predoctoral Program enables qualified graduate students from external universities to carry out doctoral thesis research under the guidance of SAO scientists at the Center for Astrophysics, Harvard & Smithsonian. Students remain under the supervision of their home institution thesis advisors. The program is open to all qualified applicants who are English-speaking citizens of all nations. The SAO Predoctoral Program is designed for graduate students wishing to carry out all or part of their thesis research at the Smithsonian Astrophysical Observatory. Therefore, applicants must have completed preliminary coursework and examinations prior to the start of the SAO Predoctoral Program. Applicants must gain approval of their home university department head. The SAO Predoctoral Fellowship is awarded for a period of six months or more depending on the project. Appointments of longer than three years (total) are unusual and are granted only under exceptional circumstances. Once the potential SAO advisor has endorsed the application, the applicant will receive a link providing access to the application form. Each applicant should arrange for letters of reference to be submitted by three individuals familiar with her or his scientific abilities. One referee must be the applicant's primary advisor at their home institution. If English is not the first language of the applicant, we recommend that the applicant convey to the reference writers that an assessment of their English proficiency be included in their letter. The SAO Predoctoral Program accepts applications twice a year, May 1 and November 1, for start dates within the following year. Please visit the award's website for more information.