We present extensions of the entropy rigidity results of Ledrappier-Wang and Besson-Courtois-Gallot to the class of RCD metric spaces. These are the metric-measure spaces with a weak notion of Ricci curvature being bounded from below. RCD spaces arise as a natural class of metric spaces closed under measured-Gromov-Hausdorff limits of manifolds with Ricci curvatures bounded from below. For this reason, they have been intensely studied over the past decade. From our results we are also able to also derive new corollaries about manifolds. This is joint work with Xianzhe Dai, Jesus Nunez-Zimbron, Raquel Perales, Pablo Suarez-Serrato and Guofang Wei. Speaker(s): Chris Connell (Indiana University)