Peer health com­mu­ni­ties offer a broad base of per­sonal health exper­tise, but uncov­er­ing men­tors with shared cir­cum­stances takes time, effort, and can yield advice that doesn’t quite fit one’s sit­u­a­tion. To address this chal­lenge, we are col­lab­o­rat­ing with an online can­cer com­mu­nity to iden­tify men­tor­ship char­ac­ter­is­tics of com­mu­nity mem­bers, develop social match­ing tools to con­nect suit­able peers for men­tor­ship, and assess the value of social match­ing for peer men­tor­ship. Find­ings will enhance our under­stand­ing of patients’ peer sup­port needs and improve the way we meet those needs.