The 2015 ION Mini-Symposium on Glial Cell Development and Function was held at the Institute of Neuroscience on June 19th, 2015. Profs. Benjamin Deneen (Baylor College of Medicine, USA), Changjoon Justin Lee (Institute of Science & Technology, Korea), Masamitsu Iino (University of Tokyo, Japan), Marco Prinz (University of Freiburg, Germany) presented their recent findings. Prof. Muming Poo gave the opening remark and Prof. Jiawei Zhou hosted this symposium. More than 150 researchers from ION, Second Military Medical School, Shanghai Jiao Tong University Medical School, Fudan University Medical School, attended this symposium.