The COVID-19 pandemic has caused unexpected disruptions to Western countries which affected women more adversely than men. Previous studies suggest that gender differences are attributable to: women being over-represented in the most affected sectors of the economy, women’s labour market disadvantage as compared to their partners, and mothers taking a bigger share childcare responsibilities following school closures. Using the data from four British nationally representative cohort studies, we test these propositions. Our findings confirm that the adverse labour market effects were still experienced by women a year into the COVID-19 pandemic and that these effects were the most severe for women who lived with a partner and children, even if they worked in critical occupations. We show that adjusting for pre-pandemic job characteristics attenuates the gaps, suggesting that women were over-represented in jobs disproportionately affected by COVID-19 pandemic. However, the remaining gaps are not further attenuated by adjusting for the partner’s job and children characteristics, suggesting that the adversities experienced by women were not driven by their relative labour market position, as compared to their partners or childcare responsibilities. The residual gender differences observed in the rates of active, paid work and furlough for those who live with partner and children point to the importance of unobserved factors such as social norms, preferences, or discrimination. These effects may be long-lasting and jeopardise women’s longer-term position through the loss of experience, leading to reinforcement of gender inequalities or even reversal of the progress towards gender equality.