The ongoing pandemic has dramatically disrupted daily life, increasing the risk of developing psychiatric disorders and poor mental wellbeing. The compound effects of social, political and psychological stressors have increased psychological symptoms among adolescents and young people, with worries about COVID-19 playing a central role in the clinical course of their mental health problems caused by the pandemic. The aim of this cross-cultural study was to examine the social psychological effects of COVID-19 on adolescents’ and young people’s mental health and wellbeing in Ibero-American population. Participants involved 6,283 adolescents and young adults from five different Spanish-Speaking countries (83.7% female) aged between 12 and 30 years ( M = 18.79; SD = 3.48). Participants completed the Worries about COVID-19 and its Consequences Scale (W-COV), the Satisfaction with Life Scale (SWLS), and the Depression, Anxiety and Stress Scale (DASS-21). Descriptive analyses, multivariate ANOVAs and Pearson correlations were performed, as well as Structural Equation Modelling (SEM) testing a mediational model. The results indicate cross-cultural difference in COVID-19 related worries, emotional symptoms and life satisfaction. Results from SEM confirmed the overall indirect effects of COVID-19 cases, political response and participants’ conditions during lockdown on depression, anxiety, stress and life satisfaction mediated by COVID-19 related worries. These findings suggest that the social psychological factors underlying psychological symptoms could be partly explained by increased worries about COVID-19 and its personal, social, economic and political consequences, which may offer guidance to policy makers and health services for safeguarding youth mental well-being.