The COVID-19 pandemic has pushed many employees away from their offices into their homes. During the first wave of the COVID-19 pandemic, in early spring 2020, most countries recommended or required that employees work remotely from home to reduce the spread of infection at workplaces and during travel to and from these workplaces. The main aim of this study was to investigate the relationships between working from home, work/life conflict and mental wellbeing in Europe during the pandemic. The study was based on a large-scale, online survey that was conducted during the COVID-19 pandemic three times, in 2020, 2021 and 2022, in 27 EU countries, and included 53 214 respondents that were employed at the time of the study. The results showed that working from home, work-to-life conflict and life-to-work conflict has increased and that mental wellbeing has decreased during the pandemic. Our regression analyses showed that the number of hours worked from home was negatively associated with work-to-life conflict and positively associated with life-to-work conflict. These results indicate that working from home can have both positive and negative consequences for employees' work/life conflict. The regression results showed that hours worked from home, work-to-life conflict and life-to-work conflict were negatively associated with mental wellbeing. It is important to consider different work situations for different working life groupings when implementing work-from-home measures. Organizations must consider how work is supervised and help managers understand how to support employees to achieve work-life balance when working remotely.