We report the formation of GaAs nanowires (NWs) containing In0.2Ga0.8As/GaAs quantum dots (QDs) on patternedAl(0.65)Ga(0.35)As/GaAs distributed Bragg reflectors (DBRs) grown on GaAs(111) B substrates. The growth conditions of both GaAs and A(l0.65)Ga(0.35)As layers on GaAs(111) B are optimized for the growth of highquality Al0.65Ga0.35As/GaAs DBRs with (111) orientation in order to obtain high reflectivity at the NW/DBR interface. Moderately high growth temperature and low V/III ratio can mitigate the formation of pyramidal hillocks, resulting in the formation of high-quality DBRs on GaAs(111) B substrates. Optical characterization at 7 K of single GaAs NW cavities containing 75-stacked InGaAs/GaAs NWQDs grown on patterned such Al0.65Ga0.35As/GaAs DBRs/GaAs(111) B substrates exhibits lasing oscillation at 1.43 eV with a threshold pump pulse fluence of 250 mu J/cm2.