**Preface to "Selected Papers from the 5th International Electronic Conference on Sensors and Applications"**

This issue of Sensors is a collection of selected papers from the proceedings of the 5th International Electronic Conference on Sensors and Applications (ECSA-5), held online on 15–30 November 2018, through the sciforum.net platform developed by MDPI. The annual ECSA conference was initiated in 2014 as an online only conference to allow unrestricted participation from all over the world, forgoing concerns regarding travel and related expenditures. This conference is of particular interest since the research concerning sensors has been rapidly expanding, and a platform for rapid and direct exchanges about the latest research findings can provide a further boost in the development of novel ideas.In total, 18 technical contributions were published after standard peer reviewing. Collectively, they present recent advances in the areas of chemical sensors, biosensors, physical sensors, sensor networks, and cutting-edge topics like smart cities, smart sensing systems and structures, structural health monitoring (SHM), and wearable sensors.
