Weight gain in psychiatric populations is a common clinical challenge. Many patients suffering from mental disorders, when exposed to psychotropic medications, gain significant weight with or without other side effects. In addition to reducing the patients’ willingness to comply with treatment, this weight gain may create added psychological or physiological problems that need to be addressed. Thus, it is critical that clinicians take precautions to monitor and control weight gain and to take into account and treat all problems facing an individual. In this review, we examine some of the key issues surrounding weight gain in individuals suffering from mental disorders for contemporary practitioners in community clinics. We describe some factors known to make certain patients more susceptible to treatment-induced weight gain and mechanisms implicated in this process. We also highlight a few psychological and pharmacological interventions that have proven effective in weight management. Importantly, we provide critical steps for management and prevention of weight gain and related issues in the clinical practice of psychopharmacology.