The present research addresses Mendelssohn’s theory of the sublime as one of the significant figures in German rationalist aesthetics. Our research obtains its significance primarily from the fact that there has been no research prior to this about Mendelssohn’s aesthetics in Persian; and secondly that even in the Continental philosophy researchers have often focused on other areas of Mendelssohn’s philosophy while his aesthetics and theory of the sublime has been overshadowed by his contemporaries such as Baumgarten and Kant. Our purpose is thus, firstly, to introduce a significant figure in German rationalist aesthetics; and secondly, to study and analyse in detail his theory of the sublime as both a bridge between German and British aesthetics and theories of the sublime with an influence on Kant, and a unique theory in itself with innovative and rich aspects. The current research is based on Mendelssohn’s texts addressing the sublime and takes as its method an in depth text study in order to reveal the unique aspects of his theory. This method has led us to the conclusion that despite Mendelssohn’s debt to Burkean theory of the sublime, his commitment to Wolffian rationalist philosophy and its corresponding aesthetic paradigm have helped him develop a very specific theory of his own which is based on and keeps at its heart the concept of perfection and other rationalist aesthetic principles while simultaneously incorporating Burkean ideas into the paradigm of his own theory; ideas which help him revise even the notion of perfection. To achieve this aim, we have introduced Mendelssohn’s aesthetic theory’s main themes in the first part of our research while moving in the second part to the more detailed and in-depth analysis of his theory of the sublime based on his main oeuvre on the sublime.