Policy documents across the globe call for citizen engagement to fight climate change emergencies and build more sustainable societies. They also recognize the key role of formal and non-formal education in preparing citizens to address those challenges. However, there is a need to identify appropriate instruments to evaluate the impact of educational interventions on people’s knowledge, attitudes, and behaviors, which are essential components of the action competence required to become environmental citizens and agents of change. The aim of this paper is to investigate the potential of the Sustainability Consciousness Questionnaire (SCQ) to evaluate different educational interventions aimed at increasing environmental citizenship. It presents three sub-studies from Spain, Belgium, and Sweden using the SCQ with varying contexts, duration, and target groups yet sharing common pedagogical features in the interventions. Pre-intervention scores indicate a common pattern of high sustainability knowingness, moderate sustainability attitudes, and lower sustainability behaviors in the three dimensions (environmental, social and economic) of sustainability consciousness, and a positive impact on sustainability behavior after the intervention. These findings are especially significant when compared to previous studies. We therefore conclude that the SCQ is useful for detecting the effects of learning interventions of varying designs and contexts that address environmental citizenship. The results are discussed in terms of key pedagogical features of the educational interventions, and the appropriateness and sensitivity of the instrument in detecting changes in the intended direction. It concludes with implications for research and practice and suggestions for future lines of work.