Background <p>Climate change and environmental degradation pose significant threats to ecosystems and human well-being, leading to increased eco-anxiety, especially among young adults. Eco-anxiety, characterized by worry and fear about environmental issues, can affect mental health and behaviours. This study aims to explore the relationships between eco-anxiety, sociodemographic factors, experiences of climate events, pro-environmental behaviours, and life satisfaction in young adults.</p> Methods <p>A quantitative cross-sectional design was employed to examine the relationships between the variables mentioned above among young adults. The sample included university students from health science centres in Spain. Surveys were used to gather data on participants’ eco-anxiety levels, sociodemographics, experiences with climate events, pro-environmental behaviours, and life satisfaction.</p> Results <p>The study revealed eco-anxiety differences among genders, with female participants experiencing greater personal impact anxiety. However, no differences were found among education or area of upbringing and residence, except that growing up/living in rural areas was associated with more behavioural symptoms of eco-anxiety. Direct and indirect experiences with climate events significantly influenced eco-anxiety levels, with direct experiences having a stronger effect. Linear regression models showed that different eco-anxiety dimensions had distinct relationships with pro-environmental behaviours and life satisfaction, with personal impact anxiety increasing pro-environmental behaviours and reduced affective/behavioural symptoms enhancing life satisfaction. Increased personal impact anxiety predicted higher levels of pro-environmental behaviours, whereas decreased affective and behavioural symptoms of eco-anxiety predicted higher life satisfaction.</p> Conclusions <p>The findings suggest that eco-anxiety is a complex and multidimensional construct influenced by several factors, including direct and indirect psychosocial experiences related to climate events and information-seeking behaviours. Eco-anxiety is differently associated with pro-environmental behaviours and mental health variables, such as life satisfaction. Addressing eco-anxiety requires a multifaceted approach that considers its different dimensions and individual differences over time. Future research should explore these relationships longitudinally and include more diverse samples to enhance the generalizability of the findings.</p>