The aim of this article is to examine the definition of knowledge among the Mutakallimūn and its relation to their theological doctrines. In this article I argued that the definitions of knowledge developed by the mutakallimūn are influenced by their theological background. In addition, I will indicate that the theologians’ different views regarding “what a definition actually is and consists of” also play a key role in their definition of knowledge. To achieve this aim, I will investigate several definitions of knowledge from the Mutakallimūn of Early Kalām from the early Ashcarites and the Muctazilites.