The production of KS0 mesons in inelastic p+p collisions at beam momentum 158 GeV/c (sNN=17.3 GeV) was measured with the NA61/SHINE spectrometer at the CERN Super Proton Synchrotron. Double-differential distributions were obtained in transverse momentum and rapidity. The mean multiplicity of KS0 was determined to be 0.162 ± 0.001 (stat.) ± 0.011 (sys.). The results on KS0 production are compared with model predictions (EPOS 1.99, SMASH 2.0, PHSD and UrQMD 3.4 models) as well as with published world data.