Electrochemistry is at the centre of energy technologies such as batteries, fuel cells and solar cells, and it plays a key role in widely used and emerging sensing and diagnostic platforms. Single entity electrochemistry provides a new way of viewing electrochemical processes at the nanoscale, and gives a bottom-up approach for understanding electrochemical processes in complex systems. Single entity electrochemistry spans a wide range of topics, from electrocatalysis and the properties of functional materials, to bioanalysis (e.g., single cell studies and DNA analysis with nanopores), but many of the underlying concepts, principles and experimental/theoretical challenges are common. This Faraday Discussion brings together leading scientists to discuss key challenges in the design, execution, analysis, theory and interpretation of single entity electrochemistry experiments, and to assess the implications of such measurements for electrochemistry and broader interfacial science.