Education is considered to be one of the key tools for addressing sustainable environmental conservation while balancing sustainable socio-economic development to achieve Gross National Happiness in Bhutan. The Environmental Science subject was introduced to prepare students with knowledge, values, and skills to address sustainability. This study aimed to investigate the alignment of Environmental Science textbooks, examinations, and the Environmental Science Curriculum Framework with each other and with Education for Sustainable Development. Four environmental textbooks, five examination sample papers, and the curriculum framework were used for the document analysis. The method involved the analysis of selected chapters from the four textbooks for classes IX to XII, followed by an analysis of the examination sample papers and finally skimming the content in all four textbooks. The textbooks and examinations were well aligned in knowledge focus, and the values related to utilization were more evident than the values on conservation. The textbooks were also well aligned with the principles and strands of the curriculum framework. However, the textbooks and assessments lacked information on students' community participation and the action-oriented content required to develop students' action competence in solving environmental problems, which is the tenet of Education for Sustainable Development.