Citizenship, as the making of citizens, is an empirical and intellectual educational process. The ability of citizens to understand the world and also their responsible and active attitude has to address the issue of sustainability in the 21st century, ie, an environment that will continue to exist for the future generations of citizens. Sustainability has emerged as a contemporary political value, as both the destruction of the natural environment and the complex social problems of humanity are threatening the development and self-realisation of humans and posing limitations, an issue of concern to the academic community and political leaders. Active and responsible political attitudes are cultivated through educational experiences and curricula that are engaging and meaningful to students. This chapter analyses the concepts of citizenship and sustainability, refers to the Sustainable Development Goals (SDGs) as defined in a UN conference (Agenda 2030) and presents ways to promote sustainability in education as well as relevant research, with a focus on the natural environment. It is concluded that a 4Cs curriculum on citizenship and sustainability is grounded οn civic and political values, developed in the conceptual framework of critical pedagogy, methodologically operates the school as a civil society forum and needs competent teachers to implement it.