There is ample evidence that optimists lead happier and healthier lives than pessimists. The link between optimism and better functioning in life has often been attributed to the more adaptive coping strategies optimists use. Meta-analytic evidence suggests that optimists use more active problem-focused coping and emotion regulation strategies, less avoidance coping, and are more flexible in adjusting their coping strategies to meet contextual demands. Research so far has focused mainly on the regulation of negative emotions and only few studies investigated whether optimism is associated with specific strategies to regulate positive emotions. The present study uses ecological momentary assessments (EMA) to examine whether, compared to less optimistic individuals, more optimistic individuals (1) use different emotion-regulation strategies to regulate their negative and positive emotions in daily life; (2) are more flexible in the emotion-regulation strategies they use in daily life; (3) are more effective in using emotion-regulation strategies in the sense that their attempts indeed result in increases of positive and decreases of negative affect and stress in daily life. Baseline data on trait optimism and EMA data on emotion-regulation, positive and negative affect, and stress will be used from an existing Dutch sample of 185 participants between 18 and 61 years old, with in total 9,263 completed momentary assessments (14 days, 5 times per day). Dynamic Structural Equation Modeling (DSEM) in Mplus 8 is used to analyse the data. Results are discussed during the presentation.