The growing debate about global environmental problems is evident in several spheres of society. The concern for the future of the planet is used as a political slogan, inspiring the creation of new laws and encouraging academic research that serves this purpose, as well as increasing the number of government agencies concerned with this matter. The 21st century is considered the “century of sustainable development”. Sustainability education in high schools has the potential to make the benefits of civil construction more visible to society and media by showing students, parents, and communities in general how sustainability in the built environment can improve their lives in economic, social, and environmental aspects. This study was applied in three high schools of Juiz de Fora (Brazil) and Guimarães (Portugal). These high schools have similar characteristics regarding teaching patterns and commitment to strengthening sustainability in their respective regions and reflect their socio-economic conditions, governmental strategies, everyday habits, and cultural attributes. The information was collected through questionnaires applied to high school students in 2017. This paper shows the need for including an indicator of sustainability awareness in sustainability assessment tools for high school buildings.