Spin–orbit coupling (SOC) is a fundamental interaction in solids that can induce a broad spectrum of unusual physical properties from topologically non-trivial insulating states to unconventional pairing in superconductors. In iron-based superconductors (IBS) its role has so far been considered insignificant with the models based on spin- or orbital fluctuations pairing being the most advanced in the field. In this review we discuss the recent direct observation of SOC by angle-resolved photoemission spectroscopy (ARPES). Electron-like Fermi surface of LiFeAs split by SOC.