In this work have been presented the theoretical studies of the halogen bond nature based on six model complexes of O≡C∙∙∙X–Y type, where X and Y are halogen atoms. In these investigations, Local Molecular Orbital Energy Decomposition Analysis (LMOEDA) and Quantum Theory Atom in Molecules have been used as well as geometrical parameters and energy of intermolecular interaction and Molecular Electrostatic Potential (MESP). LMOEDA studies reveal a strong dependency on results on calculation methods. Some techniques have been given very consistence results with expectations; however, Grimme’s dispersion corrections and some long-range separated functions in DFT do not work with used decomposition energy procedure. Electron density and Laplacian values confirm linear dependencies in connection to halogen bond energy than in the case of ΔE_int=f(RC∙∙∙X). MEP calculations clearly indicate that for studied complexes the σ-hole theory is very useful to halogen bond description.