Sports betting and other forms of gambling have increased rapidly across many African cities, including those in Nigeria, largely driven by the growth of commercial betting outlets and mobile betting platforms. Although research from high-income countries links gambling with adverse psychological outcomes, empirical evidence on the psychological determinants of gamblers’ well-being in low- and middle-income countries (LMICs) remains limited. Understanding how personality characteristics and perceived control relate to psychological health among gamblers in African settings is therefore important for informing prevention and intervention strategies. A cross-sectional survey design was employed among 300 active gamblers recruited through purposive sampling from major sports betting centres in Ado Ekiti, Nigeria. Participants completed standardized measures assessing Big Five personality traits, self-esteem, perceived controllability, and psychological health. Data were analysed using Pearson correlation, multiple regression analysis, and independent-samples t tests. Perceived controllability showed a significant positive association with psychological health (r = .12, p < .05). The Big Five personality traits did not demonstrate a significant joint effect on psychological health, F(5, 293) = 2.11, p > .05. However, extraversion (β = −.15, t = −1.69, p < .05) and neuroticism (β = .13, t = 1.93, p < .05) independently predicted psychological health. No significant difference emerged between gamblers with high perceived controllability (M = 55.96) and those with low perceived controllability (M = 54.71), t(297) = 0.93, p > .05. Personality factors and perceived controllability appear to have modest but meaningful associations with gamblers’ psychological health. Interventions targeting gamblers in Nigeria may benefit from incorporating personality-informed counselling and cognitive-behavioural approaches aimed at strengthening perceived control.