Background and aim: In preventing the collapse of the ecosystem, individual behavior plays a crucial role alongside the action of global actors, but the complex possible pathways from nature relatedness and knowledge to pro-environmental behavior (PEB) through eco-emotions have not been widely studied. Thus, the current study aimed to explore the complex relationship between environmental knowledge, nature relatedness, different eco-emotions (anxiety, guilt and grief), general PEB and the intention to change behavior in the future. Method: A representative sample of the Hungarian population (N = 1000) participated in an online study and answered questions about their environmental knowledge, PEB and intention to change their behavior, and completed the Nature Relatedness Scale, the Ecological Grief Questionnaire and the short versions of the Ecoanxiety Questionnaire and Eco-guilt Questionnaire. Results: General PEB was directly associated with higher nature relatedness (fi = 0.223, SD = 0.032), ecological grief (fi = 0.252, SD = 0.076) and the negative consequences of anxiety (fi = 0.106, SD = 0.044), while intention to change was directly associated with higher nature relatedness (fi = 0.190, SD = 0.034), knowledge (fi = 0.131, SD = 0.032, and eco-guilt (fi = 0.248, SD = 0.052 and less negative consequences of anxiety (fi = -0.109, SD = 0.055). Ecological grief and the negative consequences of anxiety positively mediated the effect of nature relatedness on general PEB, while the negative consequences of anxiety negatively mediated the effect of knowledge on general PEB and the effect of nature relatedness to the intention to change. Eco-guilt was a positive mediator between nature relatedness and intention to change. Implication: By revealing and explaining the complex relationship system between nature relatedness, environmental knowledge and eco-emotions our article provides useful insights for environmental awareness raising efforts.