Objectives Some young adults often tend to perceive interpersonal relationships and social interactions as stressful, and as such, avoid them. Seeking help from parents and interactions with neighbors during childhood are known to be important in forming positive impressions of people, thereby influencing help-seeking behavior in adulthood. However, it remains unclear how these experiences are related and how they influence interpersonal relationships in adulthood. This study aimed to investigate whether childhood experience(s) of social interactions in the community has any modifying effect on the association between seeking support from parents in childhood and avoidance of interpersonal relationships in adulthood.Methods Data pertaining to 1,274 individuals (aged 18 to 39 years) were collected from a questionnaire survey conducted in 2018 by Nagoya City of Japan. Modified Poisson regression analyses were performed to estimate the prevalence ratio of current avoidance of interpersonal relationships depending on the experience(s) of seeking help from a parent (father/mother analyzed respectively) and participating in community events in childhood. Data were stratified according to gender, and adjusted for age, parents' educational background, mother's working status in childhood, subjective recognition of economic status in childhood and seeking help from the other parent. Effect estimates were calculated to evaluate the existence of any modifying effect.Results No modifying effect of participating in community events in childhood was seen in the association between experience of seeking help from the father and current avoidance of interpersonal relationships, in either gender. Regarding experience of seeking help from the mother, a modifying effect was seen in men. Among men who had sought help from their mother, those who had participated in community events were less likely to avoid interpersonal relationships in adulthood.Conclusion In order to reduce the tendency to avoid interpersonal relationships in adulthood, childhood experiences of seeking help from the mother and participating in community events may be important, particularly for men. In addition to appropriate parental support, promoting interactive events for children in communities may mitigate the problem of poor social skills later in life.