One can fairly say that the central debate in the emrging field of meta-metaphysics has been around the problem of ontological commitment. Recently, truthmaker theory is reread as proposing a criterion of ontological commitment. In this paper, we offer a criterion of ontological commitment drawing on Armstrong’s truthmaker theory. To do that, first, the problem is elaborated. Then, a picture of Quine’s theory of ontological commitment, as the received view, is sketched. Then, comes Armstrong’s version of the truthmaker theory, and at last, we show how it could be developed as a specific theory of ontological commitment. Meanwhile, we show some implications of Armstrong’s theory of ontological commitment and compare it with the received view. For the most interesting part, we see that existential quantifiers have no roles in Armstrong's theory of truthmaking while it is notifiable to see that it stays far from the Moinongian version of ontological commitment.