Demographic factors are among those that influence environmental literacy and, particularly, environmentally responsible behaviours, either directly or due to an aggregation effect dependent on other types of variables. Present study evaluates a set of demographic variables as predictors for environmental literacy among 9th grade students from Madeira Island (Portugal). Through a survey involving 491 students, gender, place of residence (rural and urban), 8th grade Natural Sciences discipline performance, participation in school's environmental activities and, indirectly, socio-economic status were evaluated in their association to environmental literacy and, particularly, to each of its three main components: knowledge, attitude and behaviour. The results confirm three stronger environmental literacy predictors: rural or urban residence, depending on the components considered, higher marks in 8th grade Natural Sciences discipline and higher socio-economic status; and two weaker: female and participation in school's environmental activities. Our findings found support in previous studies and underline the need to center socio-demographic factors in environmental education practices. Considering demographic variables as the reflex of environmental, economic and socio-cultural contexts, our results corroborate an environmental literacy's construction framework on the light of Vygotsky's socio-cultural theory of human learning, in which real learning contexts play a fundamental role. In fact, also in environmental literacy, learning occurs through the interaction with the social environment and, to be effective, needs real learning contexts. Demographic variables confirmed as being predictors for environmental literacy in Madeira Island students seems to mirror the effects of the above framework and show strong evidences of linkage with socioeconomic status.