The development of technology, science and the economy has significantly improved the quality of people's lives. However, this has also resulted in an increase in the gap between man and nature, whose relationship is increasingly characterized as irrational. The anthropological factor is the culprit behind climate change and its effects on human health and the environment. Now that the society has begun to feel the consequences of the damage done to the environment on a global scale, there has been an increase in the interest in protecting and preserving the environment. Environmental awareness is a prerequisite for facing and solving environmental problems. It consists of three components: knowledge, attitudes and behaviors. All three components are intertwined and affect each other. Education plays a key role in raising the level of environmental awareness of children and young people. The orientation and permeation of the entire work of the school with environmental issues encourages the development of environmental awareness among its students. That is why this paper aims to examine the environmental awareness of high school students in Zagreb, and gain insight into their knowledge, attitudes and habits regarding the protection and preservation of the environment. The online survey method was used in the research, and the sample of respondents consisted of 529 high-school students in the City of Zagreb. The analysis of the research results showed that students express pro-environmental attitudes, but there is room for improvement when it comes to familiarizing respondents with certain concepts in the field of ecology and environmental protection. Also, no statistically significant difference was found in the practice of environmentally conscious habits of respondents according to gender and age, i.e. class.