<p>Mitochondrial deficits have been found in individuals with neurodevelopmental disorders (NDDs), including autism spectrum disorder (ASD). However, how mitochondria are regulated during brain development and how their dysregulation contributes to NDDs remains unclear. Mitochondria are continuously generated and degraded, dynamically remodelled through fusion and fission and actively transported to specific cellular compartments. Altered mitochondrial dynamics have been linked to several human diseases, and there is rising interest in their roles in neurodevelopment. However, most studies of mitochondrial contributions to NDDs have focused on the metabolic consequences of their dysfunction. This Review focuses on the mitochondrion itself, with particular emphasis on mitochondrial dynamics. We summarize recent advances in understanding the mechanisms that regulate mitochondrial dynamics during brain development and discuss how genetic and epigenetic alterations that affect mitochondrial dynamics contribute to NDDs. Finally, we consider mitochondrial dynamics as a potential therapeutic target for treatment of NDDs.</p>