This article offers an overview of the applications of the wire-mesh sensor (WMS) in different environments. It presents a critical review of the literature, with relevant and recent implementations, remarkably in gas–liquid and liquid–liquid flow, comparing it with other techniques. In addition, it is shown how the sensor is adapted to each application and its different geometries, showing its flexibility. The advantages and disadvantages of the use of the WMS are analyzed. This technique can provide information about local, chordal, cross-section or in-situ volume profiles/distributions of phase fraction; velocities, size and distributions of droplets/bubbles; frequency of periodic structures; interfacial area; film thickness; flow regimes and thermal distribution.