This study describes the morphometric variation among Sand Martin Riparia riparia populations in Serbia and assesses the relationship between breeding habitat characteristics and morphometric traits. Univariate and multivariate morphometric analyses based on 11 morphometric characters were performed on 233 adult Sand Martins from five populations. The populations showed differences in five morphometric traits: claw length, bill length, bill width, sternum length, and body weight. The differences were most pronounced in populations breeding at high densities in habitats under least human impact compared with urban habitats. Individuals from the Deliblato Sands Special Nature Reserve differed from all other populations in having distinctive characteristics (lower body weight, longer claws and wider bills). The morphological traits we analyzed are related to nesting, foraging and predator avoidance. Thus observed morphological variation might reflect differences in habitat characteristics.