We describe a new species of krait (Elapidae: Bungarus) from the Red River drainage in northern Vietnam. The new species differs from all congeners except its sister species Bungarus bungaroides by the combination of divided subcaudals, dorsal scales arranged in 15 rows, black and white rings on body and tail, and in color pattern of the head as well as hemipenis morphology. The new species differs from B. bungaroides, a distantly allopatric species ranging from eastern Nepal to northern Myanmar, in molecular characters and color pattern. We propose a vicariance hypothesis in which speciation coincided with the uplift of intervening mountain ranges in southwestern Yunnan (China) and/or Late Tertiary glaciations.