Koshi Highway or NH08 (previously: H08) (Nepali: कोशी राजमार्ग) is a 390 km long highway located in Koshi Province. It is a north-south highway which is understood to be the shortest highway connecting India to China across the Himalayan mountains in Nepal. Rani at Biratnagar is the starting point of the road which is connected to Jogbani in India and Kimathanka is the end point of the Koshi Highway, which is connected to Chinese town Chentang.

With the exception of 14 km of the track (Chyamptang-Ghongghoppa section of the road), the highway track had been open to traffic in 2021. The work was awarded to Nepal Army to open the remaining track. On 27 January 2025 the remaining track (Chyamptang-Ghongghoppa section of the road) was completed by the Nepal Army and the road from Indian border Jogbani to Chinese border Chentang is completely connected though road is not yet operational, as bridges on the rivers are not completed. though southern section of the Koshi Highway is not blacktopped yet.

Koshi is one of the major and older highways of Nepal.