The characteristics of the reverse leakage current of GaInN/GaN multiple quantum well light-emitting diodes (LEDs) are examined with various n-type GaN doping concentrations and interpreted by using a tunnelling current model. Changing the doping concentration of the n-type GaN influences the tunnelling probability of electrons into the conduction band and thus the reverse leakage current. Reducing the doping concentration of the top 150 nm portion of the n-type GaN layer by half decreases the tunnelling probability, resulting in decrease of the reverse leakage current by 80% at −10 V without deterioration of any forward electrical properties of LEDs.