The primary purpose of this chapter is to provide an overview, importance, and limitations of altmetric, an understudied yet increasingly important arena of study for scholars, academics, and professional researchers. Widespread use of social media tools in the discovery, dissemination, and discussion of research output, altmetric measurements are fast gaining popularity, and they supplement the traditional research metrics by tracking the number of social mentions of research articles. Altmetrics focuses on the publication itself, not the journal or publisher. Citations take time to build, but altmetrics shows current discussion and societal and economic engagement.