K2-133 is a cool M-dwarf (about 0.46 solar masses, 3,655 K, 0.46 solar radii), 75.2 light-years from Earth. K2-133 b is a planet with 1.3 Earth radii, with an orbital period of 3.1 days, at 0.032 AU from its star, discovered in 2017 via transit. K2-133 c is a planet with 1.6 Earth radii, with an orbital period of 4.9 days, at 0.043 AU from its star, discovered in 2017 via transit. K2-133 d is a planet with 2.0 Earth radii, with an orbital period of 11.0 days, at 0.075 AU from its star, discovered in 2017 via transit.