| Longchaeng | |
| Official Name: | Longchaeng district |
| Settlement Type: | District |
| Subdivision Type: | Country |
| Subdivision Name: | Laos |
| Subdivision Type1: | Province |
| Subdivision Name1: | Xaisomboun |
| Unit Pref: | Imperial |
| Population Total: | 8834 |
| Population As Of: | 2015 |
| Timezone: | ICT |
| Utc Offset: | +7 |
Longchaeng (Lao: ເມືອງລ້ອງແຈ້ງ, in Lao pronounced as /mɯ́aŋ lɔ̂ːŋ tɕɛ̂ːŋ/) is a district of Xaisomboun province, Laos.
In November 2015, unrest broke out in the province, killing three soldiers and three civilians. The Lao government imposed a curfew in the north-central part of the province in early-December, but in January 2016 a bomb was set off at a road construction site near Pha Nok Nok village in the district, killing two Chinese officials and injuring another. On 30 December, a bomb had previously been defused at Namphanoy village along the same road. As a result, on 16 February 2016, Major General Thongloy Silivong, a military officer who is the former chief of the National Defense Academy, was appointed the governor of Xaisomboun Province to tighten control.[1]