Background: Friendship quality is crucial for psychological well-being, yet is often lower in persons with intellectual disabilities compared to their peers. This study explores the predictors of friendship quality among adults with mild intellectual disability, focusing on age, gender, living setting, psychiatric traits, and social cognition. Method: The sample comprised 62 adults with mild intellectual disability (32 males, 30 females; ages 19-53), and 30 with significant psychiatric traits. Tools included the Friendship Quality Scale, Edinburgh Social Cognition Test, MINI PAS-ADD scale, and a demographic questionnaire. Results: Social cognition and age were the strongest predictors of friendship quality, with higher social cognition scores and younger age correlating with better quality. Gender, living setting, and psychiatric traits had less impact. Conclusions: Social cognition and age are primary determinants of friendship quality in adults with mild intellectual disability, suggesting that interventions to enhance social cognition may benefit this population's social well-being.