This paper investigates whether generation matters in the intention to buy green and sustainable products and, simultaneously, examines the antecedents of green and sustainable buying behaviour among three different generational cohorts (X, Y, and Z). By doing this, the present paper fills the gap regarding studies addressing the relationships between age and sustainable behaviour which have not included actual green and sustainable buying intention, along with the gap regarding studies only focussing on one or two (X and Y) generational cohorts. Drawing on the generational cohort theory, and by using a survey approach involving three samples of specific generations (X, Y, and Z), as well as by testing several hypotheses through ordinary least squares regression models, the paper finds that: (a) age plays a key role in the choice of green and socially friendly products, and (b) environmental concern and perceived consumer effectiveness are strong antecedents of green and sustainable purchase behaviour for all generational cohorts. This is also true for environmental citizenship, but this only applies to generations Y and Z.Finally, collectivism is only an antecedent of sustainable purchase behaviour for generation Z.