The long-tailed macaque (Macaca fascicularis) is a primate often found in Indonesia, with the current IUCN Red List status being endangered. One of the habitats of this species is the Kalisalak Forest. The social behaviour of this species has never been studied much; therefore, further research is needed on this site. This study aimed to analyse the frequency and duration of social behaviour of seven age groups of each sex. The study was conducted from April to July 2021. The research used scan sampling and continuous recording rules with 15-minute intervals (8:00 am-5:00 pm). The social behaviour data were analysed by ethogram percentage and compared with each social behaviour and age group using a statistical correlation test. The results show that the highest frequency is playing (42.92%), then grooming (41.29%), while the lowest is agonistic (8.33%), and then mating (7.46%). The duration of grooming (57.61%) is higher than playing (42.39%), while agonistic and mating are not counted because they are event behaviour. No frequency correlation (p-value>0.05) between grooming and age exists. A frequency correlation (p-value<0.05) between playing, agonistic, and mating with age group. There is no correlation (p-value>0.05) between the age group’s duration of grooming and playing.