COVID-19 pandemic has brought about many uncertainties and adversities for young people, negatively influencing their mental health. The present study investigated the mediation role of intolerance to uncertainty (IU) in the relationship between social emotional learning (SEL) skills and happiness, and between SEL skills and life satisfaction (LS) of young people, within the framework of Positive Youth Development (PYD). The study included 589 university students (51% women) aged 18-24, and the participants completed a Demographic form, Social Emotional Learning Scale-Young Adult Form, Intolerance to Uncertainty Scale, Satisfaction with Life Scale, and Oxford Happiness Questionnaire. In the study, the mediating role of IU on the relationship between SEL skills and happiness (Model 1) and between SEL skills and LS (Model 2) were tested. The analysis first indicated positive direct relations of SEL skills with happiness and LS, as well as negative direct relations with IU. In addition, there were negative associations between IU and happiness, and between IU and LS. The results also demonstrated the mediation role of IU on the relationships between SEL skills and both happiness and LS. These findings confirmed the pivotal role that SEL skills play in happiness and LS by reducing the impact of IU, thus promoting PYD during the pandemic.