In light of current pressures within formal social care services, informal carers assume an important role in meeting the care needs of a growing number of older people. Research suggests relationships between care-giving and health are complex and not yet fully understood. Recently, wide-ranging associations between sleep and health have been identified, however, our understanding of the links between care-giving and sleep is limited at present. This study assesses longitudinal patterns in co-resident care-giving and problematic sleep among older people in the United Kingdom. Our sample included 2,470 adults aged 65 years and older from the UK Household Longitudinal Study. Problematic sleep was defined as two or more problems in going to sleep, staying asleep or sleep quality. Using logistic regression models, we assessed how co-resident care-giving status, intensity and transitions influence the likelihood of problematic sleep in the following year, adjusting for potential confounding factors. Adjusted analyses found co-resident care-givers were 1.49 (95% confidence interval = 1.06–2.08) times more likely to report problematic sleep in the following year, relative to those not providing care. Care-giving over 20 hours per week and continuous co-resident care-giving also significantly increased the odds of problematic sleep. This suggests older co-resident care-givers may be at greater risk of incurring sleep problems than non-care-givers. Further longitudinal research is needed to investigate care-giver-specific consequences of poor sleep.