Vocalisations of tropical birds are still largely unexplored particularly the nocturnal species. This study examined and quantitatively described the territorial calls and duets of the Sunda Scops-Owl (Otus lempiji), Brown Boobook (Ninox scutulata) and Spotted Wood-Owl (Strix seloputo) based on 105 territorial call and four duetting recordings collected from one forest reserve and oil palm smallholdings in Selangor, Peninsular Malaysia. Wilcoxon signed-rank tests found significant differences (p<0.05) for almost all vocal parameters measured from the spectrograms derived from the duets with one higher-pitched than the other. Being the first study to describe the vocal structure of the duetting calls of the three Malaysian strigids, this study serves as a baseline for future behavioural study of nocturnal birds particularly pertaining to conspecific interactions in the Sunda region.