Background: Age estimation of unidentified human remains is an essential for establishing the biological profile of unidentified human remains. Previous studies have investigated the value linear measurements of the frontal sinus for age estimation while the value of two-dimensional (2D) geometric morphometric measurements have not been explored for this purpose. Objective: This study aims to evaluate the morphological variation of frontal sinus among adults Malaysian for age estimation using 2D geometric morphometric methods. Methods: Lateral skull radiographs of 453 adult Malaysians, comprising 151 young adults (20–39 years old), 150 middle-aged adults (40–59 years old) and 152 old adults (60–79 years old), were retrieved retrospectively. Eight 2D landmarks were applied to digitalized radiographs using TPSDig2 software. 2D geometric morphometric analysis was performed by MorphoJ software. Results: Procrustes ANOVA revealed no significant differences in shape and size (p-value > 0.05) of frontal sinus between the three age groups. However, Canonical Variate Analysis showed significant differences for Mahalanobis and Procrustes distances (p-value < 0.05) between young and old adult groups. Discriminant Function Analysis after cross-validation demonstrated an age classification accuracy of 53.5 %. Conclusion: The study suggests that 2D geometric morphometric analysis of the frontal sinus cannot be reliably used to estimate the age of an unknown Malaysian individual.