Planetary urbanisation is a critical concept and theoretical framework that posits urbanisation as a process extending across the entire planet, fundamentally transforming all landscapes and integrating them into a global urban condition. This approach challenges conventional understandings of the urban as limited to built-up areas, arguing for a totalizing logic of capitalist urbanisation that produces space on a planetary scale. As a research field and methodological approach, it investigates the manifold ways diverse territories, from metropolitan cores to remote resource frontiers, are incorporated into and shaped by global urban networks, infrastructure systems, and circuits of capital accumulation. Its key characteristics include the rejection of the urban/rural dichotomy, an emphasis on the production of space through extended processes beyond traditional urban boundaries, and a focus on the interconnectedness of seemingly disparate landscapes within a single, globally integrated urban fabric. The concept's significance lies in providing a comprehensive analytical lens for understanding contemporary global social, economic, and ecological transformations as manifestations of this extended urbanisation process, thereby informing critical analyses of global inequality, environmental change, and spatial justice.