This is a plain language resource intended to support survivors and their advocates understand the role and potential impact of  Substitute Decision Makers (SDM) in relation to navigating healthcare support. It explores what a SDM is, their level of authority, supportive definitions, and the ways in which a SDM can cause harm and abuse their power. The resource also importantly outlines protective mechanisms that can be used to work against SDM harm. This resource was developed in collaboration with Pro Bono Students Canada.