The article discusses the freedom of belief between humanism and religious thought. And since each one of humanism and religious thought has theoretical principles that usually contribute to issuing their worldviews and promote their viewpoint towards freedom of belief; therefore, the article begins with showing those principles, and explaining each one's viewpoint towards the matter of freedom of belief. Based on the centrality of man, humanism sees that freedom of belief lies in irreligiosity, or at least in the doubting about the validity of religion, besides accusing the religious thought of confiscating freedom of belief in various ways. In fact, religious thought has confirmed the matter of freedom of belief, according to some important elements; such as the denial of compulsion in religion, and that freedom of belief is the axis of reward and punishment in the Hereafter, and the rejection of violence.The most important finding the study has got to is that humanism, despite its attractive slogans, has not offered to man his real freedom of belief. And as for true religious thought, it has given to man his freedom of belief; for true religious thought sees that the confiscating of freedom of belief, in any ways, contradicts the wisdom, on which the foundation of divine legislation has been built due to the fact of trying human beings by letting them free in their choices.