Background: Universal masking, with additional layered prevention strategies, was an essential tool for limiting the transmission of SARS-CoV-2 and ensuring a safe return to in-person learning for kindergarten through 12th grade (K-12) students and staff. Few studies have examined mask adherence in this setting and none have described types of masks worn or locations of mask adherence. This project sought to assess mask adherence, types worn, and location of mask adherence in K-12 settings. Methods: This study used direct in-person observations to measure the proportion of persons wearing masks correctly; type of masks worn; and location of mask adherence in 19 K-12 schools in Georgia. Results: A total of 16,222 observations were conducted. Among those observed, 85.2% wore masks, with 80.3% wearing the mask correctly. Persons in high school were less likely to wear masks correctly. Correct mask use was most often observed among persons wearing N95-type masks. The prevalence of persons wearing masks correctly in transitional spaces was 5% higher than in congregate spaces. Conclusion: In K-12 schools with a universal masking policy, correct mask adherence was high among individuals. Examining adherence to recommended prevention measures can provide K-12 schools feedback to inform targeted messaging and policies during future disease outbreaks.