We fabricated shape-determined InGaAs/GaAs quantum dots (QDs) on GaAs (n11)B (n = 2-7) substrates using metalorganic vapor-phase epitaxy. Atomic force microscopy showed that low-index facets {100}, {110}, and {111} mainly bound QDs. The influence of substrate orientation on the QD shape and formation is discussed. The equilibrium shape of coherent strained islands is controlled by facet surface energy and elastic relaxation energy. The photoluminescence spectrum of QDs bounded by low-index facets shows clear dependence on polarization but no polarization was observed in LSQDs. Spectral polarization anisotropy showed a signature uniquely sensitive to QD shape.