KMT-2022-BLG-0440L is a Sun-like G-type star (about 0.53 solar masses, 5,778 K), 3,500 light-years from Earth. KMT-2022-BLG-0440L b is a 15.4-Earth-mass planet, at 1.900 AU from its star, discovered in 2023 via microlensing. Microlensing detections occur when a foreground star's gravity briefly magnifies a background source, revealing planets that are otherwise too faint and distant to observe directly. KMT-2022-BLG-0440L b orbits at roughly the distance of Mars from the Sun. Its low mass makes KMT-2022-BLG-0440L b a Neptune- or super-Earth-class world rather than a gas giant.