NN Ser is a bright A-type star (about 0.54 solar masses, 57,000 K), 516 light-years from Earth. NN Ser d is a 2.19-Jupiter-mass companion, with an orbital period of 7.89 years, on an eccentric orbit (e ≈ 0.24), discovered in 2010 via eclipse timing variations. NN Ser c is a 9.71-Jupiter-mass companion, with an orbital period of 19.1 years, on an eccentric orbit (e ≈ 0.09), discovered in 2010 via eclipse timing variations. NN Ser adds another data point to the growing catalogue of planetary systems whose masses, orbits, and host-star properties constrain models of planet formation.