TOI-1883 is a cool M-dwarf (about 0.49 solar masses, 3,554 K, 0.51 solar radii), 115 light-years from Earth. TOI-1883 b is a 13.7-Earth-mass planet, with an orbital period of 4.5 days, at 0.042 AU from its star, and an equilibrium temperature near 544 K, discovered in 2024 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. TOI-1883 b skims its star closer than Mercury orbits the Sun.