Diffusion imaging has been used extensively over the last decade or so to study healthy brain maturation during childhood and adolescence. Methods vary greatly across studies, but studies consistently report nonlinear maturation that continues into young adulthood, with the most protracted development occurring in frontal-temporal connections. These diffusion changes suggest increasing myelination, axonal packing, and/or coherence with age. Less consistent findings have been reported for specific timing of development (e.g., age at peak), and sex differences. Emerging new methods and large longitudinal or multi-site studies will greatly add to our understanding of brain development over the next few years.