“Faculty of imagination” is one of the Divine blessings and human tools of perception that if not employed and managed properly, it would have destructive impacts on man and his destiny. Illusion is regarded as one of human disorders in psychology and is a wrong perception; i.e. a perception of feeling that does not conform to reality or truth. The word “illusion” is not used in the Holy Qur’an; but it seems that such words as ẓann (qualm), ḥasab (suppose), za‘m (contention) are used to imply the concept of illusion. The research shows that the Holy Qur’an has stressed [the existence of] various types of illusion in man such as dichotomizing Lordship, nihilistic view of creation, contentment with the worldly gains, megalomania, etc. and has provided techniques for eliminating various kinds of illusion. These techniques are based on two cognitive and behavioral methods. Among the most important approaches presented on the cognitive basis are improvement of attitude, warning, emphasis on foresight, and encouragement of realism; and the behavioral method includes providing objective patterns and inflicting punishment.