The issue of menstrual hygiene is inadequately acknowledged and has not received proper attention. Use of sanitary pads and washing the genital area are essential practices to keep the menstrual hygiene. Unhygienic menstrual practices can affect the health of the girls and there is an increased vulnerability to reproductive tract infections and pelvic inflammatory diseases and other complications. Therefore, the objective of this study was to assess the knowledge and practice of menstrual hygiene among high school girls at Nekemte town, Oromia region, Western Ethiopia.