Introduction:Despite the high burden of tobacco-related diseases experienced by Samoans and Tongans, there is relatively little understanding of the factors that influence their smoking behaviors which could inform effective smoking cessation strategies. This study examined several psychosocial characteristics that intertwine to predict smoking patterns in these Pacific Islander subgroups. Methods:Samoans and Tongans between the ages of 18 and 33, who consumed at least 100 cigarettes in their lifetime and were current smokers, were categorized as light, moderate, or heavy smokers. Baseline data from a randomized controlled smoking cessation trial were analyzed. Participants (n = 278) were measured on self-efficacy, perceived stress, sensation seeking, hostility, depression, and impulsivity. Least square means estimated from General Linear Models were used to compare psychosocial characteristics across smoking groups, as well as by gender and ethnicity. Results:Samoan male heavy smokers reported higher levels of self-efficacy compared to light smokers, and greater stress, hostility, depression, and urgency over moderate smokers. Samoan female heavy smokers demonstrated greater stress and hostility than moderate and light smokers. Tongan female heavy and light smokers had significantly elevated levels of sensation seeking compared to moderate smokers. Tongan male smokers did not display any meaningful associations with these psychosocial constructs. Conclusions:This study underscores the important distinctions between smoking patterns, gender, and ethnic subgroups. Interventions that rely on aggregated smoking profiles or general Pacific Islander data may not adequately address the complex array of mental health factors that contribute to tobacco use.