  The CDF and D0 collaborations have recently reported a large forward-backward
asymmetry in the ttbar system which deviates from the next to-leading order QCD
standard model prediction. We study the asymmetry in the ttbar system within
the framework of singlet extensions of the Minimal Supersymmetric Standard
Model. For this purpose, we introduce non-renormalizable couplings between
first and third generation of quarks to scalars. We analyze two limiting cases
of the model, characterized by the size of the supersymmetric mass for the
singlet superfield. We study both the small and large limits of this mass
parameter. We find that in the region of small singlet supersymmetric mass we
can obtain a large asymmetry while being consistent with limits on the ttbar
production cross section. These results are also consistent with constraints
arising from flavor physics, quark masses and top quark decays.
