To evaluate the effect on school attendance of a menstrual hygiene intervention that distributes educational booklets to school children and menstrual hygiene kits to schoolgirls in northern Ethiopia. Attendance was tracked for 8839 students in grades 7-12 during the 2015-2016 academic year when the intervention was implemented. Negative binomial regression was used to test whether student sex predicted post-intervention school absences when controlling for grade-level and pre-intervention absences. Similar attendance data were analyzed for 3569 students in grades 7, 9, and 11 for the 2014-2015 academic year as a historical comparison. Over 12 211 educational booklets were distributed to students and 5991 menstrual hygiene kits were distributed to schoolgirls. After the intervention, girls had 24% fewer school absences than boys. Sex was not a predictor of absences during a similar time-period in the prior school year. This is one of the first large studies to show a positive relationship between a menstrual hygiene intervention and girls' school attendance. These positive results suggest such interventions should be expanded to other schools in northern Ethiopia. Future research should explore whether similar interventions can also decrease the rate at which girls drop out of school around menarche.