We present the discovery of three small planets transiting K2-136 (LP 358 348, EPIC 247589423), a late K dwarf in the Hyades. The planets have orbital periods of 7.9757 +/- 0.0011, 17.30681(-0.00036)(+0.00034), and 25.5715(-0.0040)(+0.0038) days , and radii of 1.05 +/- 0.16, 3.14 +/- 0.36, and 1.55(-0.21)(+0.24) R-circle plus, respectively. With an age of 600-800 Myr, these planets are some of the smallest and youngest transiting planets known. Due to the relatively bright (J = 9.1) host star, the planets are compelling targets for future characterization via radial velocity mass measurements and transmission spectroscopy. As the first known star with multiple transiting planets in a cluster, the system should be helpful for testing theories of planet formation and migration.