We report reducing the density of threading dislocations (TDs) in stacking-fault-free semipolar (202¯1) GaN grown on sapphire by inserting an AlGaN/GaN superlattice (SL). We have studied the influence of AlGaN/GaN SL on the reduction of TDs and found that the density of TDs decreases by more than a factor of three with increasing the number of AlGaN/GaN SL pairs up to 10. Furthermore, blue light emitting diodes (LEDs) have been grown on semipolar (202¯1) GaN/sapphire templates with inserted 10 pairs of AlGaN/GaN SL showing doubled light output power in comparison with the LEDs grown without AlGaN/GaN SL. © 2020 Elsevier B.V.