This study examined the moderating effect of self-esteem on the relationship between optimism and life satisfaction in final year university students. A correlational survey design was utilized. Two hundred and twenty-three university final year students of a Nigerian university consisting of 124 males and 99 females aged 24.67±2.56 participated in the study. Data were collected with a structured self-report questionnaire containing satisfaction with life scale (α = .82), Rosenberg self-esteem scale (α = .86), and life orientation test -revised (α = .79). Data were analyzed with SPSS v.23 at 0.05 significant level. Self-esteem significantly moderated the relationship between optimism and life satisfaction as indicated by a significant increase in proportion of the variance in life satisfaction when the interaction term between optimism and self-esteem was added to the regression model [ΔR2 = .03, ΔF (1, 219) = 7.26, p < .008, b = .188, t(220) = 2.69, p < .01]. It was concluded that the predictive impact of optimism on life satisfaction of university final year students is enhanced by their self-esteem; thus, students should be exposed to environment and program that promotes the development of high self-esteem and optimistic life orientation to enhance their well-being.As positive psychology becomes more popular, studies focusing on life satisfaction and associated factors such as