In this paper, the Schur multiplier and irreducible projective character tables IrrProj(G, cci) with corresponding factor sets alpha(i) for each maximal subgroup G of the sporadic simple Mathieu groups M-11, M-12 and the automorphism group Aut(M-12) of M-12 are computed. These tables IrrProj(G, alpha(i)) are obtained from a so-called representation group R of G with the aid of a code which is written in the computational algebra system GAP. In fact, this GAP code can be used to compute the projective character tables for any finite group G on condition that we can find a representation group R of G and its ordinary irreducible characters Irr(R).