Municipal and agricultural biowaste are a significant portion of the global waste stream and represent an environmental challenge that must be addressed sustainably. The literature on the topic has increased dramatically, and a bibliometric analysis is a necessary guide through this ever-growing production. This study gives an objective overview of the state of the art and topic evolution of biowaste within sustainability/circular economy frameworks. This bibliometric analysis serves as a starting point for further qualitative research, while offering opportunities for future collaborations. Two parallel searches were conducted in Scopus, agri-food/agricultural (2391 papers) and municipal (264 papers) biowaste within sustainability/circular economy concepts, and analyzed with VosViewer (version 1.6.20.0) and Excel (version 1808). This review analyzes the following: annual scientific production and countries involved, showing the US and Italy as leaders on both topics; most productive authors (only 0.2% wrote at least five papers) and affiliations and underlying international, even if static, collaborations; most influential publications and sources (Science of the Total Environment, Journal of Cleaner Production, Sustainability); evolution of keywords over time; and strengths and limitations of the bibliometric approach. It also highlights the potential for future research and collaboration. Furthermore, it underlines waste management’s evolution from a sustainable point of view towards a circular economy approach and differences between municipal and agricultural biowaste scientific production.