  The minimal supersymmetric extension of the standard model allows for some of
the coupling strengths to be complex parameters. The presence of such imaginary
phases can lead to violations of time reversal invariance, which can be tested
if correlations in products of an odd number of polarizations and momenta are
measured and found to be different from zero. As an example, we consider the
triple product $\mbox{\bf J} \cdot \left(\mbox{\bf p}_1 \times \mbox{\bf p}_
{2} \right)$ in the $\beta$-decay of the neutron, of the $\Sigma^-$, and in the
decay $K^{+}_{3\mu}$. For these low-energy decays, we find that the present
experimental precision is not enough to provide useful bounds on combinations
of such phases and the masses of the supersymmetric particles. At higher
energies, the same time reversal violating correlation in the semileptonic
decay of the $t$ quark is of the order of $\alpha_s/\pi$, made bigger by the
large mass of the decaying quark.
