<p>Summertime pollution has frequently occurred in Attica Region, Greece, an area that is greatly affected by high temperatures and Heat Waves (ΗWs). Heat-related air pollution is a major issue but sometimes disregarded in the face of the immediate effects of ΗWs. More concurrent ΗWs and air pollution events, especially ozone (O₃) episodes are likely to occur during the next decades, and a key question is about meteorological conditions behind their appearance, and their joint effects. In this study, we used data on O₃ concentrations and meteorological parameters in Attica Region, for the period 1991–2021, to investigate the O₃ pollution regime during the ΗWs period. The purpose of the study was twofold: (1) to investigate the interrelationships between key biometeorological indices during HW periods, and (2) to analyze O₃ episodes driven by HW events in the Attica Region, Greece.</p>