Abstract: Modern surveys provide access to high quality measurements on large areas in the sky and span large redshift ranges—thus sampling the galaxy distribution in detail also in the emptier regions, voids. Void cosmology is becoming an increasingly active sector of galaxy clustering analysis: by measuring void properties, such as the void size function or density profiles, it is possible to constrain cosmological parameters. Voids are particularly sensitive to the properties of dark energy and are a powerful tool to test modifications of the laws of General Relativity. In this talk I illustrate the use of cosmic voids as a tool for cosmology, I present recent developments in the field and discuss the constraining power of voids to be observed by upcoming surveys.