Objective This study aimed to investigate the association between gaming time and problematic game use (PGU) within a large sample of Korean male gamers and to examine the potential moderating effects of loneliness, living alone, and household size.Methods This study employed data from 743 male gamers from the National Mental Health Survey 2021, a nationally representative survey of mental illness conducted in South Korea. Self-reported data on the average gaming time per day, severity of PGU, loneliness, living alone, and household size were used.Results Gaming time was positively associated with PGU and this relationship was significantly moderated by loneliness such that the positive effect of gaming time on PGU was greater when the levels of loneliness were high. The three-way interaction effect of gaming time, loneliness, and living alone was also significant, in that the moderating effect of loneliness on the relationship between gaming time and PGU was significant only in the living alone group. However, household size (i.e., number of housemates) did not moderate the interaction between gaming time and loneliness among gamers living with housemates.Conclusion These results suggest the importance of considering loneliness and living arrangements of male gamers, in addition to gaming time, in identifying and intervening with individuals at heightened risk of PGU.