Ab initio calculations have been carried out at the MP2=full level with 6-311++G(3df,2p) basis functions to determine the equilibrium geometries and binding energies of the 1:1 gas-phase complexes between CH4 and HX (X = F, Cl, Br). Single-paint MP4 calculation at the MP2 optimized geometry has also been performed to include the effect of higher order electron correlation in the binding energy. Contrary to the earlier experimental and low-level theoretical investigations, it is observed that the nonconventional hydrogen-bonded structure is the most stable complex for all the three hydrogen halides. This occurs when the proton of HX forms a weak hydrogen bond to the center of one of the methane tetrahedral faces to form a symmetric top C-3v dimer. Symmetry-adapted perturbation theory (SAPT) analysis has been carried out to understand the nature of the farces involved in the bonding and also to examine how different interaction energy components vary with the change in intermolecular distance. It has been observed that the binding energy of the (CH4, HX) dimer decreases in the order HF > HCl > HBr.