Education for Sustainable Development focuses on improving environmental knowledge to combat misinformation and promote sustainable behaviours. In two experiments, we investigated whether retrieval practice, known to foster lasting knowledge acquisition, is a useful tool for (1) increasing environmental knowledge and (2) for improving environmental attitudes and behaviour (i.e., spillover effect). Participants studied a text on the effects of online streaming behaviour by means of retrieval practice or by copying the text. Knowledge gain was assessed after one (Experiment 1) and two weeks (Experiment 2). Attitudes and behaviour were assessed pre- and post-intervention. In both experiments, participants recalled more environmental knowledge after retrieval practice compared to copying. Attitudes and behaviour did not differ between both groups, but attitudes increased after the intervention in both groups. Only Experiment 1 showed declining streaming times. Our findings suggest that retrieval practice enhances lasting knowledge acquisition but barely affects environmental attitudes and behaviour.