According to Heider, some of his ideas about common-sense psychology presented in The Psychology of Interpersonal Relations ( Heider, 1958 ) originally came from his academic teacher, Alexius Meinong. However, Heider makes no reference to Meinong in his book. To clarify Meinong’s influence on Heider, we compare Heider’s explication of common-sense psychology with Meinong’s writings, in particular those on ethics. Our results confirm that Heider’s common-sense psychology is informed by Meinong’s psychological analyses in several respects: Heider adopts aspects of Meinong’s theory of emotion, his theory of value, and his theory of responsibility attribution. In addition, Heider more or less continues Meinong’s method of psychological inquiry. Thus, even without Meinong’s name attached, many aspects of Meinong’s psychology found their way into today’s social psychology via Heider. Unknowingly, some of us have been Meinongians all along.