The term "industrial symbiosis (IS)" refers to a cooperative strategy where industrial actors share services and exchange physical resources. This method improves resource efficiency and lessens the environmental effects of industrial operations within the network. It is a cooperative method in which businesses trade and reuse physical resources such as by-products, water, and energy, as well as share services such as waste management and infrastructure. It has several advantages, such as (i) lowering greenhouse gas emissions through energy, process, input, disposal, and transportation savings, as well as fuel substitution; (ii) cutting energy expenses; (iii) diverting waste from landfills; (iv) avoiding the use of virgin materials; (v) lowering transportation and logistics costs; (vi) lowering pollution to land, water, and air; (vii) lowering industrial water use; (viii) lowering hazardous waste; (ix) creating economic value from waste material; and (x) simplifying environmental legislation and regulation compliance. In Türkiye and Denmark, the number of industrial companies is rapidly increasing. These industries consume many resources (such as raw materials, water, electricity, natural gas, coal, etc.) and generate a large amount of solid, liquid, and gaseous waste. IS is gaining popularity as an approach for improving the sustainability of industrial systems. The efforts to develop IS have emerged as a critical issue over the last decade in these two European countries. The paper presents the current implementation of IS in Türkiye and Denmark’s process sectors, focusing on well-known IS practices.