AbstractWhat are the differences between optimists and pessimists? The aim of this study is to analyze the differences reported by optimists and pessimists in terms of three psychological variables: emotional intelligence (EI), happiness, and life satisfaction. To answer this question, we examined the extent to which a combination of different levels of optimism and pessimism can differently predict EI, happiness, and life satisfaction in two independent samples (891 adults, 494 adolescents). To do that, we introduced a person-centered approach, which offers several advantages in the study of optimism over the extended, predominant variable-centered approach. Then, using a latent profile analysis, we identified three groups of individuals with a similar optimism–pessimism configuration: optimists, ambivalents, and pessimists. The results obtained supported our hypothesis that optimists report higher EI, happiness, and life satisfaction levels than those reported by pessimists. Low levels of optimism, rather than high levels of pessimism, distinguish optimistic from non-optimistic people in the prediction of external outcomes. Our results suggest that optimism and pessimism can be viewed as separate yet correlated traits that can be grouped together to explain individual affective and cognitive differences, which encourage the refinement of strategies and interventions used in psychology practice.