Students who do not file the free application for federal student aid (FAFSA), or who file after the priority application deadline, are at risk of not receiving grant aid that could help them persist and graduate from college. This study used data from the beginning postsecondary student study (BPS:04/06) to examine FAFSA filing behavior (i.e. early, late, did not file) among students attending community colleges, public 4-year, and private non-profit 4-year institutions. Results indicate that later filers, on average, receive less total state and institutional grant aid compared to students who filed earlier. Attending college part-time and delaying enrollment into college after high school were strongly associated with not filing a FAFSA and filing late. There were notable differences in FAFSA filing across institutional sectors as a function of students' gender, race/ethnicity, income status, high school context, and pre-college academic experiences. These findings serve as the basis for recommendations aimed at increasing the rates of early FAFSA filing among students at the greatest risk of leaving money on the table.