Sensors have emerged as crucial tools in various fields, particularly in environmental monitoring and healthcare diagnostics, driven by increasing global health and environmental concerns. Among the promising materials, metal borides, or MBenes, have gained attention for their tunable electronic properties, large surface area, and chemical stability. MBenes demonstrate exceptional potential in both gas and biosensing applications due to their high conductivity and surface reactivity, making them adept at detecting low concentrations of hazardous gases and selectively interacting with biomolecules. This review discusses recent advances in the synthesis, structural modifications, and functionalization of MBenes, emphasizing their role in enhancing sensor selectivity and sensitivity. It also explores theoretical and experimental insights into their interactions with target analytes while outlining the challenges and opportunities for their integration into practical sensing systems. Key achievements include the development of MBene-based gas sensors capable of detecting ultra-low concentrations of gases such as NO2, NO, CO, CO2, NH3, SO, SO2, humidity and various fluorocarbons (e.g., C4F7N, C5F10O, CF4, C3F6, COF2) with unprecedented sensitivity and fast response times. Additionally, MBene-based biosensors have demonstrated remarkable performance in detecting biomolecules and pathogens, offering significant improvements in detection limits and specificity compared to traditional sensing platforms. This review concludes by outlining future research directions aimed at further enhancing MBene-based sensor performance, exploring new applications, and integrating these materials into practical sensing technologies for environmental monitoring, healthcare diagnostics, and industrial process control.