The aim of this paper is to a) investigate the environmental attitudes of generational cohorts using the New Ecological Paradigm (NEP) scale, b) explore whether social marketing campaigns are perceived as helpful, c) report whether participants are members of an environmental association or organisation, and d) examine existing intergenerational cohort differences in environmental attitudes and perceived effectiveness of social marketing campaigns. A questionnaire was used for data collection employing a nonprobability sampling targeting adults from 18 years old. Data were obtained and analysed from a sample of 2295 valid responses from four different generational cohorts (Generation Z, Y, X, and Baby Boomers). Results reveal that a) participants have moderate environmental attitudes based on the mean values (MV) of the NEP scale statements, b) participants perceive that social marketing campaigns will help to change people’s attitudes and behaviour towards environmental issues, c) the vast majority of participants are not members of any kind of environmental association or organisation, and d) generational cohort differences were found in all three dimensions extracted from factor analysis of the NEP scale, while no statistical differences were detected regarding perceptions of the social marketing campaigns. The results suggest that adequate environmental education through the school curriculum and the use of social marketing campaigns on environmental issues will eventually reflect actual positive environmental behaviour of citizens, and thus need to be implemented.