We will present the most recent results on leptonic B decays $B^{\pm(0)} \to K^{* \pm (0)} \nu \bar{\nu}$ and $B^{\pm} \to \mu^{\pm} \nu$, based on the data collected by the BaBar detector at PEP-II, an asymmetric $e^+ e^-$ collider at the center of mass energy of the $\Upsilon(4S)$ resonance.