The recent observation of the same-sign dimuon charge asymmetry in the B system by the D0 collaboration has 3.9 σ deviation from the standard model prediction. However, the recent LHCb data on s B neutral-meson mixing do not accommodate the D0 collaboration result. In this paper, considering the effect of Z ′ -mediated flavour-changing neutral currents in the 0 0 q q B B − (q = d, s) mixing, the same-sign dimuon charge asymmetry is calculated. We find the same-sign dimuon charge asymmetry is enhanced from its SM prediction and provides signals for new physics beyond the SM.