Considering the importance of spiritual health in maintaining and improving one's mental health, the current study aimed to study the role of trust in God in the formation, maintenance, and development of mental health. In this review study, keywords such as "trust in God", "believers", and other synonymous words were searched in national and international databases. Moreover, the characteristics of prophets, saints, and believers were studied in Quran and Quran commentaries. The review of Islamic resources indicated the numerous effects of trust in God on mental health. In fact, one who trusts in God can attain personal coherence by believing in the unity of divine acts. Moreover, one's tolerance can be reinforced by giving meaning to world’s catastrophic events and sufferings. Strong willpower for decision-making, adaptation to the environment, inner peace and confidence, freedom from disappointment and despair, return from wrongdoing, patience, and hope for God's blessings and forgiveness are among other major effects of faith in God on mental health. Considering the effects of trust in God on different aspects of human life, attention to this religious teaching can pave the way for confronting life's unpleasant events and becoming a healthy human being. Therefore, it is necessary for health authorities to institutionalize this Quranic teaching to confront disruptive factors for mental health.