The present disclosure provides methods and uses of Slit protein and nucleic acid for inhibiting fibrosis and fibrotic-related disorders, for example, of the kidney, lung, heart, liver, or a wound. The Slit protein can be, for example, Slit2 or Slit2-N, or a Slit variant that can bind the Robo receptor and induce signalling. Also provided are pharmaceutical compositions comprising the Slit protein or nucleic acid and an additional anti-fibrotic agent.