OBJECTIVES: The aim was to investigate associations between caregiving and adiposity using a representative UK longitudinal study. We also investigated whether associations differed by age, gender and caregiving characteristics. METHODS: Data on 9,421 participants aged 16+ from three waves (2009-2012) of the UK Household Longitudinal Study were used. Body mass index, waist circumference and percentage body fat were assessed. Caregiving and caregiving characteristics (hours per week, number of people cared for, co-resident caregiving and combining working and caregiving) was available from the prior wave. Gender-stratified associations between caregiving/caregiving characteristics with adiposity were tested. Covariates included caregiver's health, socioeconomic position, parenthood and partnerships. RESULTS: Caregiving was associated with higher adiposity for women but not men. Younger women caregivers had particularly higher levels of adiposity. Men combining part-time paid work with caregiving had higher levels of adiposity than men working full-time and not caregiving. Women aged 16-44 or 65+ had particularly high levels of adiposity when combining full-time work and caregiving, compared to full-time work alone. CONCLUSION: The health of caregivers should be a public health priority, particularly for younger women and those combining paid work with caregiving responsibilities.