A spin-flavor symmetry emerges for baryons in the large-N_c limit. Large-N_c baryons form irreducible representations of the spin-flavor algebra, and their static properties can be computed in a systematic expansion in 1/N_c. Symmetry relations for static baryon matrix elements are obtained at various orders in the 1/N_c expansion by neglecting subleading 1/N_c corrections. Equivalent relations arise in the quark and Skyrme models, which satisfy the same large-N_c group theory as QCD. The 1/N_c expansion yields useful results for QCD baryons with N_c=3.