This thesis is about fieldwork in ecology education. We live in a troubled era of ecological breakdown and as we witness the effects of the climate crises and the loss of biodiversity, questions of education are brought to the fore. The aim of the thesis is to empirically and theoretically investigate what ecological fieldwork does and what significance ecological fieldwork can have for ecological literacy. Research on ecological literacy includes ecological and socio-political knowledge, awareness of environmental issues, environmentally responsible behaviours, cognitive skills (scientific inquiry and analysis), and affect. Occasionally, critical aspects and holistic and spiritual components are included. Research on fieldwork ecology education highlights the importance of place, opportunities for slow explorations, emotional experiences, the inevitably unpredictable nature of the field, and aesthetic dimensions. New materialist and posthumanist perspectives have had a major impact in research on children’s encounters with other species. I extend these perspectives to older learners and highlight the role of materiality in fieldwork as central to the growth of ecological literacy. The dissertation contributes to the conceptualisation and understanding of ecological literacy and the scope of ecological literacy is broadened to include material relational aspects. The theoretical framework is non-anthropocentric, relational and process oriented. Theoretical positions and analytical concepts of mainly Donna Haraway and Bruno Latour are employed for understanding encounters with other organisms and materiality in ecological fieldwork. The overarching research questions are: How do students establish relationships with other species and non-living things in ecological fieldwork? How are relationships significant for ecological literacy in education?The study is ethnographically inspired and based on researcher participation in two educational fieldwork settings in Sweden. The first study is of an upper secondary school nature guide course. Two teachers and a student group overnight in a nature reserve to experience black grouse lekking and the ecology of a bog. The second is of a folk high school course focusing on sustainability and nature connectedness. This one-year part-time course had outdoor gatherings arranged around different themes one weekend a month. The empirical material consists of video and audio recordings from both locations with a focus on nonhuman–human encounters and relationships. The results show that fieldwork provides opportunities for students to encounter nonhumans in a way that is not possible in a classroom. The practicality of the fieldwork foregrounds the actual nonhuman–human encounters, and the notion of ecological literacy is reformulated and expanded to include a practice of becoming-with grounded in relational materialism. The results can be used to further explore how fieldwork education practices can be developed to acknowledge nonhuman–human relational aspects and to incorporate emotions along the whole register. Contemplative practices and serious playfulness may work as educational means and contribute to emotional fieldwork events. Education must offer spaces for learners to explore and tell new stories of becoming-with, about living in a shared complex world in which grief, loss and suffering are entangled with joy and wonder.