DOCK3 is a member of the DOCK family of guanine nucleotide exchange factors that regulate cell migration, fusion, and viability. Previously, we identified a dysregulated miR-486/DOCK3 signaling cascade in dystrophin-deficient muscle which resulted in the overexpression of DOCK3; however, little is known about the role of DOCK3 in muscle. Here, we characterize the functional role of DOCK3 in normal and dystrophic skeletal muscle. Utilizing Dock3 global knockout (Dock3 KO) mice, we found haploinsufficiency of Dock3 in DMD mice improved dystrophic muscle pathologies, however complete loss of Dock3 worsened muscle function. Adult Dock3 KO mice have impaired muscle function and Dock3 KO myoblasts are defective for myogenic differentiation. Transcriptomic analyses of Dock3 KO muscles reveal a decrease in myogenic factors and pathways involved in muscle differentiation. These studies identify DOCK3 as a novel modulator of muscle health and may yield therapeutic targets for treating dystrophic muscle symptoms.