This study employs hierarchal linear modeling to examine whether high school grade inflation occurred between 2010 and 2021, including for students who were tested during the pandemic. The study does so while simultaneously accounting for student and school characteristics. This is the first study, to the current authors' knowledge, that makes use of this analytic approach in understanding grade inflation. The authors sought to understand the degree to which both individual-level and school characteristics might be related to grade inflation across years and whether such characteristics had a differential effect across time. This study largely concerns itself with these research questions: (1) Is there evidence of grade inflation between 2010 and 2020 for students who took the ACT as graduating seniors? Is grade inflation similar across different points in the ACT scale? (2) Does grade inflation vary by racial/ethnic background, gender, percentage of students eligible for Free or Reduced-Price Lunch (FRL) at the school, or percentage of students of color at the school while controlling for other student and school characteristics? and (3) Does the evidence of grade inflation among ACT test takers extend to students who graduated in 2021, the first full year of data available during the COVID-19 pandemic? The findings show evidence of grade inflation without and with accounting for student and school characteristics. Grade inflation became apparent in 2020 and 2021, with the rate of grade inflation increasing substantially during those years.