Alcohol problems occur in later life and are associated with notable social, psychological, physical and economic consequences. With an ageing population worldwide and a reported increase in alcohol consumption in older people there is growing concern over this public health issue. In order for health professionals to successfully intervene with older people who are experiencing alcohol problems, it is important to understand the underlying factors that may increase exposure to, or consumption of, alcohol. This chapter combines data from a UK-based qualitative study aimed at understanding older people’s reasoning about drinking in later life with key academic literature in order to identify the psychological and sociological reasons for drinking in old age. Individuals who have had alcohol-related problems over several decades and have survived into old age tend to be referred to as early onset drinkers and account for about two-thirds of older drinkers. Late-onset drinking accounts for the remaining one-third of older people who use alcohol excessively. Reasons for consuming alcohol can be categorised as either positive or negative reinforcement. While stressful life events, such as bereavement or retirement, may trigger late-onset drinking in some, this is not the case for all persons. Alcohol use has been associated with self-medication for both physical and mental health problems as well as insomnia. Alcohol consumption has also been linked to boredom, loneliness, isolation and homelessness. However, the direction of causality in the relationship between alcohol use and many of these factors is often in doubt. Older people also report consuming alcohol for positive reasons such as enjoyment and socialisation.