Of all the approaches to the concept of dualism in Origen’s thought, this article concerns the issue which does not seem very obvious : his understanding of the expression heteros theos. Is it possible to call Jesus “the other God”, existing aside from the only God ? Thanks to the Dialogue with Heraclides, we can judge the profundity of the issue. According to the Dialogue, heteros theos resembles the language used by Marcion, in which “the other God” means the Demiurge, an antagonist of the merciful God. But the expression also invokes the Judeo‑Christian inspired Christology, in which “the other God” signifies a manifestation of the God Jehovah, or a secondary deity, subordinate to Jehovah. In his other writings, Origen usually avoids calling Christ heteros theos, precisely because of the similarity to marcionism and monarchianism. However, forced to resolve the theological problem presented in the Dialogue, Origen decides to explain the meaning of the term “heteros”. His explanations are inspired by Aristotle’s categories, much simplified and illustrated by examples from the Bible. Origen shows that “difference” can be understood as opposition, but there are other possible interpretations of the term. More than anything, it is relative towards a particular characteristic. Origen’s argumentation, in comparison with other discussions concerning the term (Justin Martyr and Tryphon, Peter and Simon the Magician), illustrates that the understanding of God as “different” may lead to the emergence of dualistic concepts, which are often very radical.