The Leh-Manali Highway is a highway in India connecting Leh and Manali. It is open only between June and mid-September when snow is cleared from the road by the Border Roads Organisation. It connects the Manali valley to Kullu valley, Lahaul and Spiti and Ladakh. It is made part of NH 21, with completion date of 2012.

It crosses some of the highest mountain passes in the world, including Rohtang La (3,978 m, 13,050 ft), Baralacha La (4,892 m, 16,050 ft), Lachulung La (5,059 m, 16,600 ft) and Taglang La (5,325 m, 17,470 ft). The latter 2 passes are less problematic over former 2 due to less snowfall in Ladakh. A tunnel is being constructed to bypass Rohtang pass to make the highway an all-weather road.

As the journey along the road normally takes two days (or more depending on road conditions), many tourists and travellers make overnight stops at Jispa and tented camps such as Sarchu. Alternately, overnight stops can be made at Keylong. Stretch between Manali and Sarchu is 222km (in Himachal Pradesh state), and that of Sarchu and Leh is 257km, with total highway length of 479km. Owing to the high altitudes and the oxygen-rarefied air, many travellers experience mountain sickness or in some cases even acute mountain sickness.

An important credit is that the Leh-Manali Highway was designed, built, constructed, (and is maintained) in its entirety by the Indian Army and is capable of supporting the heaviest of their vehicles.