Ab initio, many-body methods are used to determine structures, relative energies, and vertical electron-detachment energies of ScC6H6-. The two lowest anionic structures are singlets that display boat and inverse-boat conformations of the C6H6 ligand and have energies that are within 0.1 eV of each other. The principal peaks in a recently reported anion photoelectron spectrum are assigned to Dyson orbitals that are dominated by Sc 4s or 3d(x)(-y)(2)(2) contributions in the boat form or by Sc 4s or 3(xy) contributions in the inverse-boat form. A triplet with C-6v symmetry is the third most stable state of the anion.