The Geosciences and Environmental Education teacher-training degree course at a public university in São Paulo State is celebrating its 20th anniversary this year. It was established at the Geosciences Institute (USP) with the main objective of preparing and qualifying teachers, citizens and students to understand Earth’s dynamics and the causes and consequences of natural and anthropogenic processes, and to think and act with consideration for the sustainability and the complexity of the planet. In this sense, it is a pioneering undergraduate program in Brazil that focuses on interdisciplinarity and connects Earth sciences with social sciences. Teacher training is strongly linked to current research in environmental sciences, and students learn geoscientific knowledge, see and comprehend the connections in science, develop skills to solve environmental problems, and understand the connections and dynamism of Earth’s system. This paper highlights some examples of interdisciplinary approaches using innovative teaching practices and field classes, taking into account regional and local contexts whenever possible and bringing students closer to the reality of our society. Since its implementation, many students have been teaching in public schools and have developed environmental education projects that promote an integrated and critical comprehension of Earth.