Neutrino-electron scatterings are purely leptonic processes with robust standard model (SM) predictions. Their measurements can therefore provide constraints to physics beyond SM. The {nu}{sub e}-e data taken at the Kuo-Sheng Reactor Neutrino Laboratory were used to probe two scenarios: nonstandard neutrino interactions (NSI) and unparticle physics. New constraints were placed on the NSI parameters ({epsilon}{sub ee}{sup eL},{epsilon}{sub ee}{sup eR}), ({epsilon}{sub e{mu}}{sup eL},{epsilon}{sub e{mu}}{sup eR}), and ({epsilon}{sub e{tau}}{sup eL},{epsilon}{sub e{tau}}{sup eR}) for the nonuniversal and flavor-changing channels, respectively, as well as to the coupling constants for scalar ({lambda}{sub 0}) and vector ({lambda}{sub 1}) unparticles to the neutrinos and electrons.