In peer relations research, interest is increasing in studying the neural underpinnings of peer experiences in order to understand how peer interactions relate to adjustment and well-being. This review provides an overview of 27 studies examining how positive and negative peer experiences with personally familiar peers relate to neural processes. The review illustrates the ways that researchers have creatively designed controlled functional magnetic resonance imaging (fMRI) experiments employing real-life relationships. The review highlights evidence supporting the role of reward and affect sensitivity, as well as neural sensitivity to social exclusion in relation to peer experiences. Further, the review highlights research about how peer experiences modulate neural underpinnings of risk-taking and prosocial behavior. The review concludes with the challenges that studies aiming to combine peer and brain research face and provides avenues for future research.