  We provide a general analysis of time reversal invariance violation in the
exclusive semileptonic B decays B to D l nu and B to D* l nu. Measurements of
the lepton and D* polarizations can be used to search for and identify
non-standard model sources of T violation. Upper limits are placed on the T-odd
polarization observables in both the supersymmetric R-parity conserving and
R-parity breaking theories, as well as in some non-supersymmetric extensions of
the standard model, including multi-Higgs-doublet models, leptoquark models,
and left-right symmetric models. It is noted that many of these models allow
for large T-violating polarization effects which could be within the reach of
the planned B factories.
