School and nursery closures and homeworking during the Covid-19 crisis have resulted in an immediate increase in unpaid care work, particularly for parents. Amongst contemporary couples in the UK, women spent more time than men doing housework, childcare and caring for adults prior to the crisis; thus, lockdown draws new attention to gender inequality in divisions of unpaid care work. This study aims to answer how couples in the UK divided childcare and housework during lockdown and whether this is associated with changes in levels of psychological distress. Data for this study come from the April and May waves of Understanding Society Covid-19 study. Psychological distress was measured using the GHQ score (ranges from 0 to 36). Unpaid care work included men and women’s hours spent on childcare and housework and the impact of increased unpaid care work on employment schedules. We found that every week, women spent 5 more hours on housework and 10 more hours on childcare than men during lockdown, and this increased housework and childcare was associated with higher levels of psychological distress for women. One-third of parents adapted their work patterns because of childcare/ homeschooling. Men and women who adapted their work patterns had on average 1.16 and 1.39 higher GHQ scores than those who did not. This association was much stronger if he or she was the only member in the household who adapted their work patterns, or if she was a lone mother. Only 10% of fathers reduced work hours due to care work compared to 20% of mothers. Fathers had more psychological distress if they reduced work hours but she did not, compared to neither reducing work hours. Our research suggests that lockdown has hit people with young families and lone mothers particularly hard in terms of mental health, and continued gender inequality in divisions of unpaid care work during lockdown may be putting women at a greater risk of psychological distress.