The possibility of inducing value change has attracted interest among scholars and practitioners in developmental and social psychology. This study proposes a new web-based intervention aimed at enhancing the importance adolescents ascribe to social-focused values (i.e., self-transcendence and conservation), which was implemented and evaluated in the context of online schooling during the COVID-19 pandemic. Social-focused values primarily regulate how one relates to others and preserve cooperative relations. These values were found to predict positive outcomes, such as adolescents' well-being, school performance, prosocial behavior, and, most recently, COVID-19 preventive behaviors. The intervention was carried out with a group of 140 high school students (Age: M = 16.53, SD = 0.95) living in Italy during the pandemic. The intervention group (N = 84) completed four tasks, which were based on the value-changing mechanisms of priming, consistency maintenance (raising awareness and knowledge of prosociality), or direct persuasion (trying to convince another person to act prosocially). The intervention significantly increased the importance of conservation values (i.e., tradition, conformity, security) but not of self-transcendence values (i.e., universalism, benevolence) in the intervention group in comparison to the control group (N = 56). This result reflects the reality during the pandemic, where prosociality was more easily expressed through behaviors consistent with conservation values instead of self-transcendence values, which emphasize (physical) proximity to others. The effectiveness of the intervention was further supported by a qualitative analysis of adolescents' writings while completing the tasks. Limitations of the study, future research developments, and practical implications for values education in secondary schools are discussed.