MXenes are two-dimensional nanomaterials with several admirable properties that have attracted interest in sensing systems and environmental applications. These materials present high surface area, regular layered structure, adjustable elemental composition, high chemical activity, excellent electrical conductivity, and unique mechanical properties. The synthesis of MXenes can be approached from two perspectives. One is the top-down method, which involves processes like chemical etching or photo-Fenton, and the other is the bottom-up approach, exemplified by techniques such as chemical vapor deposition. Because of its broad applicability, studies have explored various possibilities for modifying MXenes, including organic and inorganic modifications, resulting in different chemical groups on the surface. Incorporating these groups into MXenes can facilitate the development of sensors for detecting various chemical compounds with wide-ranging applications. Recent advances have broadened the scope of MXenes-based materials, opening new horizons for environmental monitoring, photocatalysis, adsorption, and wastewater treatment applications. This chapter aims to provide an overview of the recent innovations in applying MXenes to develop sensing platforms for monitoring organic and inorganic contaminants in environmental samples. Furthermore, the main challenges and opportunities to be explored in new applications are also addressed.