Motivational interviewing (MI) as a counseling approach has gained empirical support for its use in a number of settings and for a variety of behaviors. However, the majority of practitioners trained to use MI have been professionals rather than laypeople. This article presents the rationale, design, and evaluation of an MI-based training for cancer survivors and caregivers to deliver peer support. The training and evaluation of the peers ("guides") to encourage practice and increase research knowledge for using MI-based peer support models for cancer care are discussed. Thirteen cancer survivors and two caregivers received two-day DVD-based MI training, as well as supplemental monthly sessions for six months. The guides demonstrated MI proficiency as assessed by the MI Treatment Integrity scale and other process evaluation assessments. MI can be adapted to train laypeople to provide support for groups such as cancer survivors.