Ligand field theory (LFT) calculations of energy levels were performed for the neutral actinide monooxides (AnO) and their singly and doubly ionized cations (AnO⁺ and AnO²⁺ by treating the molecular electronic states as An^m+ free-ion energy levels (where An ∈ Th through Lr and m=1, 2, 3, or 4) perturbed by the electric field of O^2- or O^-. LFT parameters obtained from fits to the energy levels of ThO, ThO⁺, UO, and UO⁺ were used to compute molecular energy levels for the lowest energy (maximum Sc, maximum Lc) 5f-core states of An⁴⁺, An³⁺, An²⁺, and An⁺ for the majority of the An⁴⁺O^2-, An³⁺O^-, An³⁺O^2-, An²⁺O^-, An²⁺O^2- , and An⁺O^- electronic configurations. Simple linear relationships enabled predictions of the dissociation energies for AnO, AnO⁺ and AnO²⁺ (where An ∈ Bk through Lr) and ionization energies for AnO and AnO⁺ (where An ∈ Bk through Lr), mainly based on recent accurate experimental data for the ionization energies of An atoms (where An ∈ Fm, Md, No, and Lr) and correlations with the energetics of the atoms and ions.