  The BaBar experiment has recently obtained some important results in the
search for new physics in leptonic and lepton flavor violating decays,
exploiting the complete datasets collected at the $\Upsilon(4S)$,
$\Upsilon(3S)$ and $\Upsilon(2S)$ energies. In particular, new limits on the
ratio $\Gamma(\Upsilon(1S)\to\tau^+\tau^-)/\Gamma(\Upsilon(1S)\to\mu^+\mu^-)$,
on lepton flavor violating decays of the $\Upsilon(3S)$ and $\Upsilon(2S)$, and
on $\tau$ decays to three charged leptons or $\tau\to e/\mu \gamma$ are
presented.
