The international workshop on UV materials and devices (IWUMD-2018) will be held on December 7-9, 2018, at Kunming, China. It follows the second conference held on November 14-18, 2017 at Fukuoka, Japan. The conference will focus on deep discussion of growth, physics and devices on Ultraviolet (UV) materials including AlN, BN, Ga2O3 and so on. The workshop will feature invited, oral and poster sessions. We hope this conference offers an opportunity for exchanging ideas and enjoying constructive discussion by focusing on UV materials and devices.