In bees, both body size and shape may show considerable variation associated with differences between females and males, among populations, and due to local environmental variation. We studied multiple parameters of body size and shape of the large carpenter bee Xylocopa virginica, to understand how body size and shape are influenced by sex, and by seasonal and annual variation. In addition, we compared bees from a population near the northern edge of the range (southern Ontario, ON) which experience relatively severe winters, to bees from the central portion of the range (Maryland, MD), which experience milder winters. Overall, males and females differed in linear dimensions but were more or less the same mass. Seasonal variability was investigated using ON bees. In winter, females and males had the same overall mass, but male thoracic volume and linear dimensions such as head capsule width, intertegular width, and costal vein length, were all larger for a given mass. In summer, males weighed less than females, due to loss of mass from the abdomen. Year-to-year differences in size and shape were indicated in MD bees, which exhibited significant differences in linear dimensions and dry mass, but not wet mass. In addition, northern bees were smaller than southern bees in terms of linear dimensions, but it is not entirely clear if overwintering mass differs. We suggest that seasonal and sex differences in size are related to the different flight activity patterns of males and females in summer, and that geographic differences between the two populations are related to the length and duration of winters.