Care farming (also called social farming) is the therapeutic use of agricultural and farming practices. Service users and communities supported through care farming include people with learning disabilities, mental and physical health problems, substance misuse, adult offenders, disaffected youth, socially isolated older people and the long term unemployed. Care farming is growing in popularity, especially around Europe. This review aimed to understand the impact of care farming on quality of life, depression and anxiety, on a range of service user groups. It also aimed to explore and explain the way in which care farming might work for different groups. By reviewing interview studies we found that people valued, among other things, being in contact with each other, and feeling a sense of achievement, fulfilment and belonging. Some groups seemed to appreciate different things indicating that different groups may benefit in different ways but, it is unclear if this is due to a difference in the types of activities or the way in which people take different things from the same activity. We found no evidence that care farms improved people's quality of life and some evidence that they might improve depression and anxiety. Larger studies involving single service user groups and fully validated outcome measures are needed to prove more conclusive evidence about the benefits of care farming.