Panulinus ornatus is among the widest distributed spiny lobsters, the high-value seafood, and the major cultured species in several Indo-West Pacific countries. Five microsatellite markers were applied to investigate diversity, genetic differentiation, and population structure of ornate spiny lobster in Vietnam (VN), Australia (AU), and Sri Lanka (SR). P. ornatus population in AU exhibited highest genetic diversity, and SR population was the lowest one (number of effective allele; observed/expected heterozygous are 7.091±1.53; 0.787±0.11/0.819±0.05 and 6.568±1.88; 0.620±0.12/0.782±0.07, respectively). The FST value (0.006-0.012; P≤0.01) and DAPC analysis (BIC value =3) showed the disconnectivity between the three populations, while AMOVA test and clustering structure analysis showed low significant difference. Directional migration relative rates suggest that Vietnam population may act as a source for surrounding populations in the Indo-West Pacific. The present study provides data on the genetic characteristics and population structure of P. ornatus in the Indo-West Pacific.