Spirituality is a basic human drive with diverse forms of expression that make for unique thinking and as such, it is the ultimate end of human development. Constituents of spirituality may best be delineated by the humanistic perspective as it readily meets the demands of the not-so-religious today. The proposed Humanistic Spirituality Inventory is based on the humanistic spirituality model, which captures spirituality’s content domain. The inventory contains three scales corresponding to the three model components: (1) Self-actualization, which implies a mature perception of reality, spontaneity, creativity, peak experiences, personal growth, detachment, Gemeinschafsgefühl, and profound interpersonal relations; (2) Transcendence, which implies belief in the supernatural reality, self-transcendence, and a holistic approach to Being; and (3) Ultimate Meaning in Life, which entails the awareness of faith-inspired directedness and ontological significance of life. The current study ( N = 331) explores the development and psychometric properties of the instrument, that is, its content and construct validity as well as internal consistency and test–retest reliability. The results of the study support the good psychometric properties of the Humanistic Spirituality Inventory and suggest that it can be used as a proper measure in the assessment of this phenomenon.