  Minimal R-parity violating supergravity predicts a value for $alpha_s(M_Z)$
smaller than in the case with conserved R-parity, and therefore closer to the
experimental world average. We show that the R-parity violating effect on the
$alpha_s$ prediction comes from the larger two-loop b-quark Yukawa contribution
to the renormalization group evolution of the gauge couplings which
characterizes R-parity violating supergravity. The effect is correlated to the
tau neutrino mass and is sensitive to the initial conditions on the soft
supersymmetry breaking parameters at the unification scale. We show how a few
percent effect on $alpha_s(M_Z)$ may naturally occur even with tau neutrino
masses as small as indicated by the simplest neutrino oscillation
interpretation of the atmospheric neutrino data from Super-Kamiokande.
