<p>Intraspecific agonism plays a role in accessing key resources for survival and reproduction, such as food and mates, in many nonhuman primates. Female dominance and fission-fusion dynamics (i.e., fluctuating subgroup size and composition) are two adaptive strategies used by some primate species to cope with a high degree of seasonality. We investigated how seasonal fluctuations in reproductive opportunities and food availability affect group-wide agonism rates in wild black-and-white ruffed lemurs (<i>Varecia variegata</i>), a species with high fission-fusion dynamics and female dominance that exhibits strict seasonal and communal breeding but does not consistently breed annually. We conducted focal animal sampling over four years, encompassing several mating and birth seasons for <i>V. variegata</i> across two sites. We summed all agonistic interactions within the focal animal’s subgroup to calculate biweekly agonism rates. We estimated fruit and flower abundance using semimonthly phenological surveys. We found a significant effect of reproductive season on agonism, such that agonism rates were highest during the mating season (vs. nonreproductive and birth seasons), particularly in years when mating and births were observed. Subgroup size was also a major driver of agonism, with higher rates of agonism in larger subgroups, although subgroup size did not significantly affect individual rates of agonism. Fruit and flower availabilities were not significant predictors of agonism, suggesting that agonistic interactions in <i>V. variegata</i> may be mitigated by other means such as fission-fusion dynamics. Overall, these findings suggest that agonism functions as a reproductive strategy in <i>V. variegata</i>, and potentially in other female-dominant or communally breeding primate species, as a mechanism for females to exert mate choice and for males to gain access to mating opportunities.</p>