Properties of liquids at interfaces and in confinement are different from those in bulk and are relevant to a series of phenomena of natural and technological interest. Water interfaces are key to atmospheric and geochemical processes, while confined electrolyte solutions and confined ionic liquids play a crucial role in energy devices. A microscopic, atomistic understanding of solid/liquid interfaces is therefore crucial to advance both our fundamental understating of natural phenomena, as well as to improve technological devices. Molecular dynamics simulations, at atomistic resolution and at different level of theory, can provide a dynamical picture of interfaces “in operando” and help the microscopic interpretation of experiments.