HZ_evolution models the habitable histories of exoplanets by tracking how stellar evolution shifts the boundaries of the habitable zone over time. It computes planetary instellation histories as the host star’s luminosity and effective temperature change, and evaluates how long a given planet spends inside, interior to, and exterior to the habitable zone. HZ_evolution includes utilities to locate the continuously habitable zone and to estimate how evolving stellar properties affect the long-term habitability of planetary systems.