Abstract: This study investigated how pre-service teachers’ knowledge to apply Information and Communication Technology (ICT) in education can be enhanced. Pre-service teachers (N = 115) were asked to design a lesson in teams as part of a course titled Education for Sustainable Development. Their lesson plans were evaluated by a team of educational experts within the framework of Technological Pedagogical Content Knowledge (TPACK). Based on their feedback, each team revised their lesson plan before implementing it outside the school context. The teachers’ TPACK scores were measured via pre- and post-tests. The results indicate increased knowledge in almost all areas of TPACK. Further research is needed in order to explore the transfer effects of the pre-service teachers’ TPACK to other contexts, as well as long-term learning effect. Additionally, there is a need to explore different ways to involve and engage pre-service teachers in their own learning process.