We have searched for the decays B^0 → D_s^+a^-_0, B^0 → D_s^(*+)a^-_0, B^0 → D_s^+a^-_2 and B^0 → D_s^(*+)a^-_2 in a sample of about 230 × 10^6 Υ(4S) → BB̅ decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We find no evidence for these decays and set upper limits at 90% C.L. on the branching fractions: B(B^0 → D_s^+a^-_0)<1.9 × 10^(-5), B(B^0 → D_s^(*+)a^-_0)<3.6 × 10^(-5), B(B^0 → D_s^+a^-_2)<1.9 × 10^(-4), and B(B^0 → D_s^(*+)a^-_2)<2.0 × 10^(-4)
