Implementing effective environmental education strategies in schools is essential for nurturing young individuals with a sense of responsibility for sustainability. Knowledge regarding environmental attitudes and behaviour of school-aged children in Sri Lanka is limited. This study aimed to assess the level of environmental awareness, attitudes towards recovery and recycling, environmental behaviour, and overall awareness, alongside evaluating the impact of demographic parameters on these variables of secondary school students in Sri Lanka. A questionnaire-based survey with a quantitative approach (using a 35-item scale) was used in assessing 972 Sri Lankan secondary school students. The study revealed that students exhibit a moderate level of EA, attitude, and behavior, with greater familiarity when taught in school. Gender, school environment society membership, and student grade/type of school significantly affected the investigated socio-environmental aspects. Family income and residence type had no notable impact. The findings of this study offer important insights for creating focused interventions and educational strategies aimed at fostering a more sustainable, environmentally responsible younger generation within the distinct socio-cultural landscape of Sri Lanka.