Toxoplasma gondii is an intracellular protozoan parasite. Approximately 30% of the global population is infected by T. gondii. In chronically infected individuals, the parasite resides in tissue cysts, especially in the brain. There is a growing interest in the role of parasitologic agents in the causation of neuropsychological disorders. In this review, we have explained the interactions between Toxoplasma and its host, mechanisms, and consequences on neural and psychological diseases.