Electrochemical sensors have experienced remarkable changes in recent years. Particular recent attention has been given to wearable sensors owing to their considerable promise for monitoring the wearer’s health and wellness. The medical interest for wearable systems arises from the need for monitoring patients over long periods of time. These devices have the potential to continuously collect vital health information from a person’s body and provide this information to them or to their healthcare provider in a timely fashion. Such sensing platforms provide new avenues to continuously and non-invasively monitor individuals and can thus tender crucial real-time information regarding a wearer’s health. This presentation will discuss recent developments in the field of wearable electrochemical sensors integrated directly on the epidermis or within the mouth for various non-invasive biomedical monitoring applications. Particular attention will be given to non-invasive monitoring of metabolites and electrolytes using flexible amperometric and potentiometric sensors, respectively, along with related materials and integration considerations. These include advanced materials for imparting remarkable stretchability and self-healing abilities to enable epidermal biosensors to endure extreme deformations experienced by the human skin. The preparation and characterization of such wearable electrochemical sensors will be described, along with their current status and future prospects and challenges.