Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily and are expressed in a variety of tissues including skin and cells of the immune system. They act as ligand-dependent transcription factors which heterodimerize with retinoid X receptors to allow binding to and activation of PPAR responsive genes. Through this mechanism, PPAR ligands can control a wide range of physiological processes. Based on their effects in vitro and in vivo PPAR agonists and antagonists have the potential to become important therapeutic agents for the treatment of various skin diseases. PPARs can also be activated directly by phosphorylation to have ligand-independent effects. This review will discuss the physiology of PPARs relating this to skin pathology and their role as a target for novel therapies.