During cell swelling, Cl⁻ channels are activated to lower intracellular Cl⁻ concentrations and to reduce cell volume, a process termed regulatory volume decrease (RVD). We show that anoctamin 6 (ANO6; TMEM16F) produces volume-regulated anion currents and controls cell volume in four unrelated cell types. Volume regulation is compromised in freshly isolated intestinal epithelial cells from Ano6−/− mice and also in lymphocytes from a patient lacking expression of ANO6. Ca²⁺ influx is activated and thus ANO6 is stimulated during cell swelling by local Ca²⁺ increase probably in functional nanodomains near the plasma membrane. This leads to stimulation of phospholipase A₂ (PLA₂) and generation of plasma membrane lysophospholipids, which activates ANO6. Direct application of lysophospholipids also activates an anion current that is inhibited by typical ANO6 blocker. An increase in intracellular Ca²⁺ supports activation of ANO6, but is not required when PLA₂ is fully activated, while re-addition of arachidonic acid completely blocked ANO6. Moreover, ANO6 is activated by low intracellular Cl⁻ concentrations and may therefore operate as a cellular osmosensor. High intracellular Cl⁻ concentration inhibits ANO6 and activation by PLA₂. Taken together, ANO6 supports volume regulation and volume activation of anion currents by action as a Cl⁻ channel or by scrambling membrane phospholipids. Thereby, it may support the function of LRRC8 proteins.