The current geopolitical situation in the world, and especially in Europe, highlights the sustainability of each society and country in the present dimension and sustainable development in the future. The ability of the society of the future to develop itself, to provide for the sovereignty of its country, to strengthen its economy, to raise its level of prosperity, to preserve and enrich its culture is shaped and developed in today's schools and universities as the next generations are learning and studying there. They will be managing the country in the future, taking care of sustainable development of the society, the economy of their country, its security and defence, being at the heart of our country's future society. Therefore, innovations in the content of general secondary education in Latvia are needed by introducing a new subject of National Defence Training in schools. The legal basis for this has already been prepared in the form of laws and other regulations. Model curricula for general secondary education and the Youth Guard have been developed. Since in global forums as well as in scientific publications at the end of the 20th century the ecological paradigm has been justified as a transdisciplinary paradigm, but the ecological approach in human thinking, in promoting the development of children/youth, in all kinds of activities (in all areas of human activity, including education) has been justified as an imperative, which has become more and more relevant in the 21st century, the aim of the research was to substantiate the diversity of ecological approaches in the education of young people in the field of national defence. The results of the research demonstrate that the ecological approach is visible in the development of the national defence content. It is also common in the justification for the many aspects of the national defence learning environment.