Citizen science can raise people's understanding of science while helping scientists conduct their research. Yet its potential for driving transformative learning is empirically underexplored. We present the results of a preliminary study with secondary school students engaged in a long-term citizen science project, from the formulation of the research questions to data analysis and discussion. Students learnt about and increased their interest in neuroscience. They were also able to reflect on the role of science for society and valued their involvement as active participants in the research. We discuss the opportunities and challenges of approaching citizen science for transformative learning.