TOI-1801 is a cool M-dwarf (about 0.56 solar masses, 3,863 K, 0.55 solar radii), 30.7 light-years from Earth. TOI-1801 b is a 5.7-Earth-mass planet, with an orbital period of 10.6 days, and an equilibrium temperature near 494 K, discovered in 2023 via transit. The planet was found when it crossed the face of its star, producing periodic dips in brightness that reveal its size and orbital period to space-based photometry. Its low mass makes TOI-1801 b a Neptune- or super-Earth-class world rather than a gas giant.