Although reduced working time and furlough policy initiatives are widely regarded as important for economic and business reasons, little is known about their impacts on workers’ mental health at the onset of COVID-19 pandemic. Using data from the UK Household Longitudinal Panel Study data from 2018 to February 2020 and April 2020 and change score analysis, this study aims to compare mental health changes between those who worked reduced hours, were furloughed and left/lost paid work. The results suggest that at the onset of COVID-19 reduced working time and furlough can protect workers’ mental health, but only for men not for women. The gender differences remain significant even after controlling for housework and childcare responsibilities at the onset of COVID-19. These results highlight the importance of distributing paid work more equitably and formulating gender-sensitive labour market policies in protection of workers’ mental health.