Graphitic carbon nitride (g-C3N4), as a crucial sensing material has attracted intense interest for sensor devices development. Owing to its large specific surface area, excellent physicochemical stability, exceptional electronic band structure, and outstanding electronic, thermal, optical, and mechanical properties. In addition, excellent biocompatibility, unique electroluminescent and photoelectrochemical properties, g-C3N4 nanomaterials contribute to the development of fast, accurate, cost-effective, and reliable sensors. Herein, we provide a comprehensive review on the development of g-C3N4 nanomaterials-based sensors and their potential detection applications for various heavy metal analytes. Furthermore, a comparative sensing performance of sensors, current challenges and prospective of g-C3N4 based nanomaterials are outlined in detail.