Carbon-based stimuli-responsive nanomaterials are gaining much attention due to their versatility, including disease diagnosis and treatment. They work under endogenous (pH, temperature, enzyme, and redox) or exogenous (temperature, light, magnetic field, ultrasound) stimuli. Carbon-based stimuli-responsive nanomaterials can be used as smart materials with dynamically tunable physicochemical properties in response to changes in internal or external environmental stimuli. Their diverse combinations of nanostructures and molecular designs, as well as functional complexes with different carriers, create new opportunities for the development of advanced smart nanomaterials.