In Iceland, and around the world, the working environment in upper secondary schools changed dramatically with the onset of the COVID-19 pandemic. In our research, we aimed to illuminate the ever-changing working conditions of teachers in Icelandic upper secondary schools during the first year of the pandemic, especially in the context of gender and family composition. Data came from interviews with 12 teachers and surveys administered to upper secondary school teachers in 33 out of 37 upper-secondary schools in Iceland with participation from approximately one-third of the teacher population. The results show that teachers felt increasingly stressed throughout the pandemic and that gender played a significant role. Women, who often also served as primary caregivers at home, found it more strenuous to fulfil their teaching duties than men. The results raise important questions about teachers' working conditions and gender's role therein, especially in a country considered an emblem of success when it comes to gender equality.