The thesis presented in the present article is not the widely-accepted one according to which Mu‘tazilite thought indirectly influenced the birth and development of Arab rhetoric (balāġa ) as an intellectual trend at the time that witnessed the constitution of this discipline of Arab language sciences, but the more specific thesis that it was primarily in Mu‘tazilite thought that the foundations of balāġa as a technical discipline were truly elaborated. To argue this thesis, we shall proceed in two stages. In the first, we shall try to identify the indirect Mu‘tazilite sources of balāġa; that is, the theses and overall positions of this movement, an echo of which may be found in constitutive elements of the discipline. In the second, we will try to identify some of the direct Mu‘tazilite sources of balāġa on the basis of Mu‘tazilite studies directly devoted to the status of the Koranic text, and the concepts elaborated to account for it.