Consumer behaviour research is the scientific study of the processes consumers use to select, secure, use and dispose of products and services that satisfy their needs. Firms can satisfy those needs only to the extent that they understand their customers. The main objective of this paper is to study the gender differences in consumer buying behaviour of a Portuguese population when they go shopping to buy apparel products. To attain this objective a survey was developed and administered across Portugal. The findings confirm the differences between women and men especially in terms of What, Where, When, and How they buy.