Fibrosis is characterized by the excessive accumulation of extracellular matrix components, leading to loss of tissue function in affected organs. Although the majority of fibrotic diseases have different origins, they have in common a persistent inflammatory stimulus and lymphocyte-monocyte interactions that determine the production of numerous fibrogenic cytokines. Treatment to contrast fibrosis is urgently needed, since some fibrotic diseases lead to systemic fibrosis and represent a major cause of death. In this article, the role of the bioactive sphingolipid sphingosine 1-phosphate (S1P) and its signalling pathway in the fibrosis of different tissue contexts is extensively reviewed, highlighting that it may represent an innovative and promising pharmacological therapeutic target for treating this devastating multifaceted disease. In multiple tissues S1P influences different aspects of fibrosis modulating the recruitment of inflammatory cells, as well as cell proliferation, migration and transdifferentiation into myofibroblasts, the cell type mainly involved in fibrosis development. Moreover, at the level of fibrotic lesions, S1P metabolism is profoundly influenced by multiple cross-talk with profibrotic mediators, such as transforming growth factor β, thus finely regulating the development of fibrosis. This article is part of a Special Issue entitled "Physiological and pathological roles of bioactive sphingolipids". • Fibrosis, characterized by excessive accumulation of ECM, leads to tissue function loss. Treatment for fibrosis is needed. • S1P signalling plays a key role in fibrosis of different tissues such as lung, kidney, heart, liver and skeletal muscle. • S1P signalling may represent an innovative therapeutic target for treating this devastating multifaceted disease. • S1P influences different aspects of fibrosis such as the recruitment of inflammatory cells and myofibroblasts activation. • S1P action is modulated by extensive cross-talks with profibrotic mediators, finely regulating the development of fibrosis. [ABSTRACT FROM AUTHOR]