Childhood maltreatment is associated with altered brain structure and function and is a major risk factor for psychopathology, including reactive attachment disorder (RAD). However, whether changes to white matter microstructural integrity are associated with RAD is unclear. We used diffusion tensor imaging (DTI) to assess group differences in fractional anisotropy (FA) in patients with RAD (n = 25; mean age = 13.2) to typically developing (TD) controls (n = 33; mean age = 13.0). To further interpret differences in FA, additional parameters such as mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) were assessed. We found that FA values in the body of corpus callosum (CC) and in the projection and thalamic pathways, including the posterior limb of the internal capsule and corona radiata (anterior, posterior, and superior), were significantly higher in the RAD than in the TD group. Additionally, RAD group showed significantly lower RD values in the body of the CC and abovementioned pathways than TD group. Our findings indicate that RAD is associated with altered structure of the CC and projection and thalamic pathways, which may play a role in emotion regulation. The aberrant development of these tracts in RAD may reflect stress-related psychophysiological responses.