Values serve as guiding principles, motivating specific behaviors, and actions. Peers spend a considerable amount of time together, thus offering a unique platform for the acquisition and development of values. During adolescence, a stage of life when youth are actively defining their identities, peers emerge as vital social agents, contributing significantly to the process of value formation. In this article, I examine the ways peers contribute to the development of youth's values, with a focus on basic personal values theory. This theory sheds light on how and why peers play a role in shaping the values of adolescents. It examines the phenomenon of similarity in peer values ("values similarity") and explores how factors such as gender, age, and culture act as potential moderators in the relation between peers' and youth's values similarity. I conclude by summarizing key insights and proposing directions for research.