GJ 180 is a cool M-dwarf (about 0.43 solar masses, 3,371 K), 11.9 light-years from Earth. GJ 180 b is a 6.5-Earth-mass planet, with an orbital period of 17.1 days, at 0.092 AU from its star, on an eccentric orbit (e ≈ 0.07), discovered in 2014 via radial velocity. GJ 180 c is a 6.4-Earth-mass planet, with an orbital period of 24.3 days, at 0.129 AU from its star, on an eccentric orbit (e ≈ 0.09), discovered in 2014 via radial velocity. Mutual gravitational tugs between the planets can slowly reshape their orbits, preserving clues to the system's assembly.