Environmental education is widely used to increase awareness of conservation issues. The theory is that increasing knowledge will improve attitudes towards the environment. Often, environmental education is aimed at children with the assumption that this can also impact adults through intergenerational transfer of knowledge and attitudes. However, there are few detailed studies evaluating the effectiveness of environmental education on changing knowledge and attitudes, and whether any changes do transfer between generations. We evaluate the effect of a school-based education programme run by Malagasy researchers aimed at promoting lemur conservation in Eastern Madagascar. We assess changes in the knowledge and attitudes of participating children and their parents (surveying 126 children and 88 parents across four matched villages, 1 year after two of the villages received environmental education). There was very low awareness of the law protecting lemurs. Attitudes towards lemurs varied between species; with the aye-aye (considered scary) and the eastern lesser bamboo lemur (considered a pest) being less preferred. Children in villages who received environmental education had higher knowledge about lemurs and more positive attitudes than children in the villages not exposed to the environmental education. Knowledge about lemurs among parents where children had received environmental education was also higher (although not attitudes). Environmental education programmes can have a lasting effect, certainly on knowledge, but engagement of the research and NGO community is needed to build the capacity of teachers in rural areas to enthuse their pupils about ecology and conservation issues.