The effects of adsorption on the graphite(0001) surface on the nonplanar distortions of nickel(II) octaethylporphyrin were studied by molecular mechanics (MM) approach. Using the Consistent Force Field (CFF) program with previously developed parameters for metalloporphyrins and supplemented to treat intermolecular interactions geometry optimizations were carried out for 43 conformations of 28 distinct conformers of nickel(II) octaethylporphyrin. The stable energy-minimized conformers were stereochemically characterized, analyzed by the Normal-coordinate Structural Decomposition (NSD) method and compared with the available theoretical and experimental data for the isolated nickel(II) octaethylporphyrin structures.