In this communication, optimized sulfur vacancy-rich nitrogen-doped MoS2 nanoflowers were developed, which served as excellent N2 reduction reaction (NRR) electrocatalysts for the conversion of N2 to NH3 under ambient conditions. Electrochemical results demonstrated that the as-prepared N-doped MoS2 electrode afforded a superior NH3 yield and high faradaic efficiency, which exceeded those of the recently reported MoS2 catalysts. The possible NRR catalytic mechanism and electron transfer pathway were further elucidated via density functional theory calculations.