Low family income is associated with poor academic achievement among children. Higher rates of school absence and tardiness may be one mechanism through which low family income impacts children's academic success. This study examines relations between family income, as measured by receipt of free or reduced-price lunch, school attendance, and academic achievement among a diverse sample of children from kindergarten to 4th grade ("N" = 35,419) using both random and within-child fixed-effects models. Generally, results suggest that the receipt of free or reduced-price lunch and duration of receipt have small but positive associations with school absences and tardies. Poor attendance patterns predict poorer grades, with absences more associated with grades than tardies. Given the small associations between receipt of free or reduced-price lunch and school attendance, and between the duration of receipt of free or reduced-price lunch and children's grades, results do not provide strong evidence that absences and tardies meaningfully attenuate relations between the duration of low family income and student achievement; poorer attendance and persistent low income independently predict poorer grades. Implications for policy and future research are discussed.