The effect of different synthetic conditions (both template and chloride precursor concentration) on the morphologies of BaZrO₃ microcrystals was systematically investigated. Three different templates, polyethylene glycol (PEG), cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfate (SDS), and two different chloride concentrations were used in the experiments. BaZrO₃ microcrystals were obtained using the microwave assisted hydrothermal method (MWHT) at 140 °C for 40 min. BaZrO₃ microstructures were characterized by powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), Fourier transform Raman spectroscopy (FT-Raman) and photoluminescence (PL) measurements. The growth mechanism for the formation of BaZrO₃ with decaoctahedron-shape was analyzed in detail, and we have found that the nature of the mechanism follows a non-classical growth process involving mesoscale self-assemblies of nanoparticles. Based on these findings, a relationship between the morphology and the photoluminescent behavior is proposed.