The aim of this study was to document the impacts of an environmental education program with adolescents and older adults on attitudes about old age, and to investigate possible associations of these attitudes with age group, economic class, residing with grandparents, and grandparents' contribution to parenting. We investigated adolescents between 10 and 11, and between 14 and 15 years old divided into Experimental Group (EG), who participated in three intergenerational workshops at School, and Control Group (CG). The results indicated that younger adolescents had more positive attitudes than older ones and there was an association between a higher frequency of contact with grandparents and more positive attitudes in the Persona domain among 14- to 15-year-olds. There was no association between attitudes and the other variables investigated. At the end of the intervention, all EG adolescents showed more positive attitudes in the cognition domains, and older adolescents in the Agency domain.