Abstract. Everyday problem-solving situations can be approached on an independent or interdependent basis. The current article investigated the moderating effects of openness to experience and self-efficacy on the relation between an independent versus interdependent problem-solving style and negative affect (stress, anxiety, depression, and neuroticism). Australian university students ( Ns = 399, 186, 337, and 248) and international academic researchers ( N = 199) took part in research studies examining the relations between personality, problem-solving-style, and mental health. Openness to experience moderated the association between problem-solving style and negative affect in all five studies. When openness was low, independent problem-solvers reported greater negative emotionality compared to interdependent problem-solvers. Further, the moderating effect of openness to experience on trait-based negative affectivity (i.e., neuroticism) was mediated by state-based negative emotional experiences of anxiety and stress. The moderating effect of self-efficacy appraisals was only statistically significant on specific anxiety about solving problems. Openness to experience seems to help alleviate the negative mental consequences of independent problem-solvers. These findings have implications for clinical practice with regard to building a therapeutic relationship and retaining clients.