  We study the rare decays of $B_{s} \to M_s\ell \bar{\ell}$ ($M_s=\eta,
\eta',\phi$ and $\ell=\nu,e,\mu,\tau$) in the standard model. With the hadronic
form factors evaluated in the light front and constituent quark models, we
estimate the decay branching ratios, respectively. We also discuss the
longitudinal lepton polarization and forward-backward asymmetries.
