Describing and explaining the nature of imagination and its function with regard to human being and ontology has always been one of the preoccupations of philosophers and thinkers. Plato is the first philosopher who considered an epistemological status for imagination and, by dividing the world into the world of reason and world of senses, he ascribed the knowledge of imagination to the world of senses. In different parts of Mathnavi, Molavi, the great Muslim-Iranian mystic, has paid much attention to imagination, its types, its status in the Knowledge of Man (both physical and metaphysical affairs) and its various influences on the body, soul and mental states of any individual. Thus, the present article aims to compare the concept of imagination in the view of the two thinkers. For reaching such aim, while using a descriptive-comparative method, first, the definitions of imagination in Mathnavi and Plato’s ideas are investigated and, then, the similarities and differences of the two views are shown. The conclusion is that their ideas are similar with regard to unreality and shadowiness of the world and phenomena, the relation between imitation and imagination, deficiency and restrictions of imagination for understanding the reality, whereas their ideas are different regarding the power of imagination, its epistemological status and the meaning and influence of it.