The aim of this research is to examine the effect of an intergenerational interaction programme on the life satisfaction, social support and loneliness of older people. Intergenerational interactions have been considered as crucial for the creation of age-friendly societies. This research, conducted in Istanbul, Turkey, used a quasi-experimental design with a pre-test and post-test control group. The sample of the study consists of 80 older persons individuals living in a long-term care centre, consisting of a study group (n = 40) and a comparison group (n = 40). The study group participated in a 6-month intergenerational interaction programme and the comparison group did not participate in any programme. The intergenerational interaction programme was carried out between March 2021 and August 2021. The Ministry of Youth and Sports of Turkey provided financial support for the activities carried out in the project. Scales (Sociodemographic Information Form, Life Satisfaction Scale, Social and Emotional Loneliness Scale, and Multidimensional Perceived Social Support Scale) were administered to the participants as a pre-test before the start of the programme and as a post-test after the completion of the programme. Data analysis was carried out using SPSS 26.0. The independent groups t-test was used to determine the significant difference between the study and comparison groups, and the dependent groups t-test was used to compare the pre-test and post-test scores of the study and comparison groups. When comparing the pre-test scores of the study and comparison groups, no significant differences were found between the means, but when comparing the post-test scores, significant differences were found between the means. It was found that there were statistically significant differences between the pre-test and post-test scores of the older people who were included in the intergenerational programme and who participated regularly. It was found that participants' life satisfaction and perceived social support increased and their social loneliness decreased. It is believed that this study will contribute to the relevant literature by providing new information to be conducted in a different culture and to develop a different practice of intergenerational interaction. The findings may have implications for social policies to be developed for older adults in Turkey.