This paper explores the interactions between Li and oxygen in their van der Waals state for the study of cold collisions between these two species. The quartet surface was calculated using a basis set converged spin-restricted CCSD(T) method, while for the doublet state, we obtained energy splitting with respect to high-spin using both CASSCF and MRCI approaches. Our findings suggest that the interaction in the quartet state of Li–O2 is weak, with a shallow and nearly isotropic well depth of 37.5 cm−1. The shallow potential well and small reduced mass of the system allow us to predict the scattering length for all possible combinations of 6Li and 7Li with 16O2 and 17O2. This result could be useful for understanding the collision dynamics of Li-O2 in ultra-cold regime.