This article explores Karl Marx’s conceptualization of the concept of freedom, and its relation to his philosophy. Although Marx did not address the concept of freedom explicitly and directly, he did not overlook it completely. On the contrary, freedom as a concept has special significance within all his works. The interrelated materialist nature of Marx’s philosophy makes it possible to investigate and capture the concept within many of his works, and in its relation to other fundamental concepts in his philosophy such as species-being, human nature, and alienation.