DiGeorge syndrome (DGS) is one of the most common genetic syndromes, resulting from random mutations in the 22q11.2 region of chromosome 22. The effects of DGS are highly variable and include craniofacial abnormalities, cardiac defects, immune deficiencies, cognitive impairment and psychiatric disorders. The molecular mechanisms underlying the manifestations of DGS are not completely understood. Identifying specific mutations and molecular pathways involved in DGS and the resulting phenotypic characteristics are areas of ongoing investigation. Many of the manifestations of DGS have been linked to deletion of the T-box transcription factor 1 (TBX1) gene, which plays a role in neural crest cell migration, pharyngeal arch (PA) development and formation of the pharyngeal pouches. TBX1 interacts with many molecular pathways leading to craniofacial defects and aberrant neural crest cell migration and survival. Many of the psychiatric and cognitive effects of DGS have been linked to mutations in genes such as DiGeorge critical region (DGCR6), Catechol-O-methyltransferase (COMT), Phosphatidylinositol 4-kinase alpha (PIK4CA) and zinc finger, DHHC-type containing 8 (ZDHHC8) that regulate neurotransmitters and neuronal metabolism. Understanding the genetic and molecular mechanisms underlying DGS can lead to more effective and targeted therapy for patients. In this review, current findings on the genetic aspects of DGS are summarized and future directions for research are addressed.