This study was conducted in the Letkhokkon delta mangrove, Myanmar to establish species-specific allometric models for accurate aboveground biomass estimation, contributing to improved mangrove ecosystem management. We found three mangrove species (Avicennia officinalis, Sonneratia apetala and Sonneratia caseolaris), and the first two species (A. officinalis and S. apetala) were dominant. Results highlighted the distinctive stand structure, species composition, and the low Shannon diversity (H′＝0.734). Using the tree measurable parameters such as diameter at breast height (DBH), height (H) and wood density (ρ), we established several allometric models of aboveground biomass (W＝ax^b) for two dominant species. We selected the best-fit allometric models by model selection parameters. Also, we compared these best-fit models with the previously reported allometric models. Our study found that volumetric parameter (DBH²H) and ρDBH²H gave the best results with relatively higher accuracy than the other explanatory parameters. The study confirmed the importance of ρ in building of site-specific allometric model and also validated the superiority of species-specific models over generalized equations to estimate the biomass accurately. Besides, comparisons with other allometric models for mangroves in Americas, Asia, China and Myanmar emphasized the significance of tailored approaches, considering the influence of ρ on accurate biomass estimation. Wood density showed less significance in species-specific level though ρ was an important variable for generalized models. Applying ANOVA results for model comparison, the current models did not significantly differ from the previous ones. Furthermore, the mean biomass differences of current study were the least variations from the observed data among other models. It pointed out site- and species-specific models reduce the uncertainties of biomass and carbon stock estimations in comparison with the generalized models. Using the best-fit models, aboveground biomass of Avicennia officinalis stand were estimated as 13 Mg ha^－1 and Sonneratia apetala stand, 14 Mg ha^－1 of carbon. In conclusion, our study established the site- and species-specific equations for estimating mangrove biomass in Myanmar, with implications for Greenhouse gas (GHG) accounting and emission reduction.