The chart below shows school mask requirements over time in states that instituted one of those policies. In states that had a statewide mask requirement in place before the 2020-2021 school year, we use the issue date of the 2020-2021 school year guidance as the school mask requirement start date. Note that some school mask requirement end dates may not be exact since they were set to expire on the final day of the school year in individual school districts.