Badlands are among the most spectacular erosive landforms in the world, typically associated with semi-arid regions but also present in more humid environments. Although often mistaken for degraded landscapes, they are primarily the result of natural geomorphological and hydrological processes acting over geological timescales. Despite their visual harshness and high erosion rates, they do not fall within the definition of desertification as established by the United Nations Convention to Combat Desertification (UNCCD), since their formation is not predominantly driven by human activity. This paper provides an overview of the main types of badlands, their distribution across the Iberian Peninsula and beyond, and the geomorphic, hydrological, and ecological processes that define them. Particular attention is paid to their sediment dynamics, ecological functions, and potential role as indicators of environmental change. Disentangling natural erosive processes from anthropogenic impacts is key to advancing our understanding of landscape dynamics in sensitive environments