The paper discusses the problem of differentiating two types of optimism, which reflect different sides of constructive thinking, dispositional optimism (DO, generalized positive or negative expectations about the future) and optimistic attributional style (OAS, explanatory style applied to positive and negative life situations). Despite a multitude of studies focused on each of these constructs, past work didn't focus on the joint contribution of DO and OAS to activity performance and psychological well-being. In a study with university students (N=141) we found common and specific features of these two constructs as predictors of well-being and academic achievement. Attributional style was measured using the brief Success and Failure Explanatory Style Questionnaire (Gordeeva, Osin, Shevyakhova, 2009) and dispositional optimism was assessed by means of Dispositional Optimism Test (Gordeeva, Sychev, Osin, 2010). These two constructs were related and similarly predicted psychological well-being. We tested a path model, where the effect of OAS for success and failures on academic achievement and well-being was mediated by effective self-regulation, whereas dispositional optimism was directly related to well-being. The model (tested by Mplus 7.4) showed a good fit to the data (χ2 = 9,315; df = 7; p = 0,23; CFI = 0,975; NNFI = 0,957; RMSEA = 0,048). Only the OAS was associated to academic achievement and its associations with the performance and well-being outcomes were mediated by self-regulation and self-organization (skills of goal-setting, planning, and persistence).