Networks in ecology encompass almost anything that can be represented by a set of points joined by edges. For example, a food web represents the feeding relationships within a community, which underpins the structure of material and energy flows among organisms and, in turn, fosters biodiversity and ecological functions. This course consists of weekly two‑hour lectures, covering fundamental concepts about ecological networks of various forms, as well as the relevant theories, quantitative and simulative techniques, implications, and applications. While the emphasis is on general concepts, case studies will also be introduced and discussed, supplemented with recent key studies.