ObjectivesTo examine the associations of COVID-19-related changes in work with perceptions of psychosocial work environment and employee health.MethodsIn a cohort of 24 299 Finnish public sector employees, psychosocial work environment and employee well-being were assessed twice before (2016 and 2018=reference period) and once during (2020) the COVID-19 pandemic. Those who reported a change (=‘Exposed’) in work due to the pandemic (working from home, new tasks or team reorganisation) were compared with those who did not report such change (=‘Non-exposed’).ResultsAfter adjusting for sex, age, socioeconomic status and lifestyle risk score, working from home (44%) was associated with greater increase in worktime control (standardised mean difference (SMD)_Exposed=0.078, 95% CI 0.066 to 0.090; SMD_Non-exposed=0.025, 95% CI 0.014 to 0.036), procedural justice (SMD_Exposed=0.101, 95% CI 0.084 to 0.118; SMD_Non-exposed=0.053, 95% CI 0.038 to 0.068), workplace social capital (SMD_Exposed=0.094, 95% CI 0.077 to 0.110; SMD_Non-exposed=0.034, 95% CI 0.019 to 0.048), less decline in self-rated health (SMD_Exposed=−0.038, 95% CI −0.054 to –0.022; SMD_Non-exposed=−0.081, 95% CI −0.095 to –0.067), perceived work ability (SMD_Exposed=−0.091, 95% CI −0.108 to –0.074; SMD_Non-exposed=−0.151, 95% CI −0.167 to –0.136) and less increase in psychological distress (risk ratio (RR)_Exposed=1.06, 95% CI 1.02 to 1.09; RR_Non-exposed=1.16, 95% CI 1.13 to 1.20). New tasks (6%) were associated with greater increase in psychological distress (RR_Exposed=1.28, 95% CI 1.19 to 1.39; RR_Non-exposed=1.10, 95% CI 1.07 to 1.12) and team reorganisation (5%) with slightly steeper decline in perceived work ability (SMD_Exposed=−0.151 95% CI −0.203 to –0.098; SMD_Non-exposed=−0.124, 95% CI −0.136 to –0.112).ConclusionEmployees who worked from home during the pandemic had more favourable psychosocial work environment and health, whereas those who were exposed to work task changes and team reorganisations experienced more adverse changes.