Scleroderma is a fibrotic condition characterized by immunological abnormalities, vascular injury and increased accumulation of extracellular matrix proteins in the skin. Although the etiology of scleroderma has not yet been fully elucidated, a growing body of evidence suggests that extracellular matrix overproduction by activated fibroblasts results from complex interactions among endothelial cells, lymphocytes, macrophages, and fibroblasts via a number of mediators, such as cytokines, chemokines and growth factors. There is also likely to be a genetic susceptibility to the disease. Recent investigations have further suggested that reactive oxygen species (ROS) and apoptosis are involved in scleroderma. Animal models are indispensable tools for understanding the complex pathophysiology of scleroderma. In this review, current findings on the pathophysiology of human, as well as animal models of scleroderma are described, which may strengthen our understanding of the pathogenesis of, and assist in exploring new treatments for, scleroderma.