ObjectivesThe critical socialisation period for kittens is estimated to be 2–7 weeks of age. Kittens reared in shelters often have poorer outcomes due to high rates of infectious disease. Therefore, many shelters are reliant on foster care programs to improve kitten survival rates and behaviour. However, little is known about the impact of specific early socialisation factors on kitten behaviour and health. MethodsDuring a 23-month period, 598 kitten foster carers completed a kitten socialisation questionnaire. The relationships between kitten weight/age at intake, days in care, singleton status, and the presence or absence of the queen during care on kitten behaviour and disease incidence were explored. Associations with exposure to noise, adults, children, location where the kitten was kept in the home, time spent alone, and ringworm treatment were also investigated. ResultsOverall being kept in social areas of the house with less noise/activity and spending some time alone was associated with positive kitten behaviour. There was no difference in fear or anxiety responses for bottle fed kittens, singletons and those without the queen. Ringworm treatment was associated with more fearful behaviour in kittens. Conclusionsand relevance: Future foster carers should be encouraged to keep kittens in social areas of the house, whilst also ensuring kittens can spend some time alone. If the home is loud, carers should slowly introduce the kitten/s to the louder and busier areas of the house before being housed there all the time. Training of carers to use more positive reinforcement techniques for administering ringworm treatment may benefit kitten behaviour.