There is an increasing awareness regarding the importance of mental health globally due to the high prevalence of mental disorders associated with a substantial disease burden. Understanding the cultural context is particularly relevant, without which appropriate approaches that combine medical, social, and policy interventions cannot be implemented. Muslims constitute the second-largest religious group worldwide. One of the pillars of Islam is the practice of Ramadan intermittent fasting (RIF), during which healthy adults abstain from consuming food and fluids from dawn to dusk. RIF has been suggested to have beneficial effects on specific psychiatric symptoms, including reduction of anxiety and depressive symptoms. Furthermore, studies have shown that the cumulative impact of RIF may benefit neurocognitive parameters. Mechanisms of these may be related to the enhancement of the neuroplasticity process as well as a reduction of neuroinflammation. RIF may also lead to changes in growth hormone and cortisol production, which could affect mood and neurocognition. While individuals who have severe mental illness (SMI) are typically exempted from the religious duty of fasting, many choose to observe RIF. The evidence regarding the impact of RIF on these individuals’ psychiatric conditions is inconclusive. However, studies have suggested a potential adverse effect in patients with schizophrenia and bipolar disorder; hence, prudence should be maintained while advising patients who wish to fast. Taken together, the overall evidence regarding mental health and Ramadan is positive. Yet, further studies are warranted to understand the biological and psychosocial factors that affect mental health and well-being during RIF.