The concept of "will power" in philosophical and religious texts dates back to around five hundred years before Christ, but in modern psychology, this concept has had some changes and transformations. Therefore, the present study is conducted with the aim of conceptualizing will power in psychology and Islamic sources. For this purpose, in the first step, the psychological concept of "will power" and the concepts corresponding to it in Islamic sources were studied using the linguistic semantics method; and in the second step, the degree of conformity of these concepts with "will power" in Islamic sources was investigated using the descriptive survey method. The research results showed that the semantic field of "will power" is characterized in lexicology and psychology by components such as mental ability, conscious inclination, behavioral ability, decision-making, self-control and intelligent behavior. In Islamic sources, the following concepts correspond to the semantic field of "will power" in lexicology and psychology: will, desire, choice, inclination, passion, lust, love, interest, providence, determination, patience, intention, neglect, decision, taharri, Imm'a, al-manza'a, al-havi, al-israr, nakth, hamm, ibtigha, qadha, qadar, and otufa. Based on research results, in the second step, the concepts wod, hazm, Imm’a, al-manza'ah, nakth, qadha, otufa, negligence, power, and decision with the content validity index (CVI) of 0.625, 0.625, 0.625, 0.75, 0.625, 0.5, 0.5, 0.625, 0.5, and 0.75 were deleted; and 22 other concepts with good correspondence to the concept of will power in Islamic sources were retained.