A quantum chemical investigation of carbon monoxide clusters up to hexamer has been carried out at DLPNO-CCSD(T)/cc-pVTZ//TPSSTPSS-D3/aug-cc-pVTZ level. The results, for dimer and trimer, were found to be in close agreement with existing experimental and high-level theoretical results. The clusters have been found to have high propensity to form symmetric, closed caged structures. Three types of van der Waals’ interaction, namely C---C, C---O and O---O, were identified. The most stable conformers of all the clusters were found to be the most symmetric, had all the carbon atoms participating in noncovalent interactions and exhibited blue shifts for all the νC≡O frequencies. A complementary conformer was identified in each case, except only pentamer, that had same symmetry as the most stable conformer, had all the oxygen atoms participating in noncovalent interactions and exhibited red shifts for all the νC≡O frequencies.