Neurodegeneration with brain iron accumulation (NBIA) is a group of seriously devastating and life-threatening rare monogenic diseases characterized by focal iron accumulation in the brain. The main symptoms of NBIA comprise progressive movement disorder, often including painful dystonia, parkinsonism, mental disability, and early death. Currently, a single established therapy is not available to reverse the progression of these debilitating disorders. The complexity of NBIA emerged from the identification of various causative genes, and up to 15 genes have been identified to date. Although the NBIA genes are involved in different cellular biochemical pathways, they show the common characteristic of generating severe iron accumulation in the basal ganglia of the patients' brains. Thus, the molecular events that lead to brain iron overload and their important roles in the pathophysiology of the diseases are not easy to identify and are poorly understood. This review summarizes the current knowledge on NBIA disorders, with a particular focus on the data describing the role of iron in the pathogenic mechanisms.