People are not objective in their judgements about the future, but rather they have the tendency to expect that their future will be better than that of other people (Taylor & Brown, 1988; Weinstein, 1980). This bias towards positive outcomes appears for various positive and negative events (see Shepperd, Klein, Waters, & Weinstein, 2013 for a review). These distortions in judgements are related to favourable attitudes and health outcomes (see Armor & Taylor, 1998 for review) and influence the manner in which people process the information and engage in unhealthy and risky behavior (Radcliffe & Klein, 2002; Rafaely, Mantsur, BarDavid, & Meyer, 2011). However, previous literature concerning the role of personality traits, such as dispositional optimism, on the judgements of future events and factors that could explain these relationships, is very limited (see Gherasim, Mairean, & Rusu, 2016 for an exception). Moreover, to our knowledge, there is no evidence regarding the links between personality characteristics and judgements of future events on adolescent samples.Adolescence is a critical stage in terms of selecting healthy or unhealthy lifestyle behavior that will continue into adulthood (Martinelli, 1999). Adolescents have the tendency to underestimate the probability of occurrence of different negative events (e.g., automobile accidents, school aggression, divorce, and healthrelated problems; e.g., Arnett, 2000; Chapin & Coleman, 2012). Understanding the factors related to judgements of future evens represents an important step in making adolescents recognize their personal risk and take self-protective measures (Harris, 2007; Sparks, Harris, & Raats, 2003; Weinstein & Klein, 1996). In order to advance the literature, the first goal of this study was to explore the relationship between dispositional optimism and judgements about the likelihood of experiencing positive and negative life events on a sample of adolescents. Furthermore, the second goal was to investigate whether the relationship between adolescents' dispositional optimism and their judgements of events may be explained by affective states.Dispositional OptimismDispositional optimism is defined as generalized expectations of positive outcomes that determine the differences in how people cope with adversity and how they feel when they are faced with problems (Carver, Scheier, & Segerstrom, 2010). A high level of dispositional optimism has been associated with better mental and physical health, as well as with more protective practices, and resilience to stressful life events on samples of adults (see Carver et al., 2010; Rasmussen, Scheier, & Greenhouse, 2010 for reviews). Previous studies also showed that dispositional optimism is related to various indices of the adolescents' positive adjustment, such as healthcare attitudes, physical and psychological quality of life, or motivation to pursue their goals (e.g., Jones, DeMore, Cohen, O'Connell, & Jones, 2008; Mannix, Feldman, & Moody, 2009; Huan, Yeo, Ang, & Chong, 2006). Recent research suggests that optimism is a modifiable variable that can be developed in adolescents through certain psychological interventions, becoming a stable personality trait throughout adulthood (Mannix et al., 2009; Tusaie & Patterson, 2006).There is little empirical evidence about the relationship between dispositional optimism and judgements of future events, and most existent studies explored the role of optimism on judgements of future negative events (Harris & Hans, 2011). Studies conducted on adult samples showed that the optimists display more positive life evaluations than pessimists and were less likely to expect negative events in the future, such as unsafe work practices, overweight or dental health problems (e.g., Fowler & Geers, 2015; Gherasim et al., 2016; OginskaBulik & Juczynski, 2001). Other studies found no association between dispositional optimism and judgements of negative events, such as perceiving the risk of heart attack, obesity or severe acute respiratory syndrome on samples of adults (e. …