The recent intriguing measurements of RK and RK are important hints of new physics that violates lepton universality. We analyze the semileptonic decays b -> s l^+ l^-? in the framework of the B-?L extension of Minimal Supersymmetric Standard Model with Inverse Seesaw (BLSSMIS). A salient feature of this model is that one of the right-handed sneutrino can be light and the neutrino Yukawa couplings are of order one. We show that the box diagram mediated by righthanded sneutrino, higgsino-like chargino, and light stop can account simultaneously for both R_K and R_K* . Within this context, a signicant lepton flavor non-universality is generated by large neutrino Yukawa coupling