AbstractStep‐edge‐induced ordering of GaAs QDs was achieved on GaAs(110) by droplet epitaxy in a lattice‐matched GaAs/AlGaAs system. After the growth of an AlGaAs barrier layer, step‐edges along the 〈113〉, 〈112〉, 〈111〉, and 〈221〉 directions were naturally formed. On these step‐edges, preferential nucleation of Ga droplets occurred, resulting in the formation of one‐dimensionally ordered Ga droplets. By irradiating intense As4 flux, we could form ordered GaAs QDs. Some of the arrays were longer than 1 μm and the QDs in the arrays were closely packed. After capping of the QDs followed by rapid thermal annealing, the ordered QD arrays exhibited strong photoluminescence emission. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)