Humans have become the weakest point in the information security chain, and social engineers take advantage of that fact. Social engineers manipulate people psychologically to convince them to divulge sensitive information or to perform malicious acts. Social engineering security attacks can be severe and difficult to detect. Therefore, to prevent these attacks, employees and their organizations should be aware of relevant defense mechanisms. This research develops a taxonomy of social engineering defense mechanisms that can be used to develop educational materials for use in various kinds of organizations. To develop the taxonomy, the authors conducted a systematic literature review of related research efforts and extracted the main target points of social engineers and the defense mechanisms regarding each target point.