Acknowledgments in scientific and academic papers are a method of expressing appreciation and gratitude between scholars. Inside the acknowledgments section, authors usually thank different entities or individuals for their support, most commonly in terms of grants, suggestions and discussions. Social networks of authors and publications has been well studied, with an exhaustive study of nearly all network properties. However, to the best of our knowledge the social graph of acknowledgments have never been investigated. In this paper we propose building an acknowledgments graph, and study the relationships between the entities of this graph. We first describe how to extract the acknowledgments section. We then extract the entities inside the acknowledgment section, classifying them into persons or organizations. After that we take a subset of the nodes and build a directed graph between the authors of these papers and the entities being acknowledged and study the characteristics of the resulting social network.