Lancang Lahu Autonomous County (simplified Chinese: 澜沧拉祜族自治县; traditional Chinese: 瀾滄拉祜族自治縣; pinyin: Láncāng Lāhùzú Zìzhìxiàn; Lahu: Laq Cha Lad Hof Ceol Ziq Ziq Sheq) is an autonomous county under the jurisdiction of Pu'er City, in southwestern Yunnan province, China. Lancang is the same as Lan Xang, and refers to the Mekong River (known in Chinese as the Lancang) on its eastern borders and adopted by modern Laos, a Tai word meaning Million Elephants.

In 1988, the county was struck by a magnitude 7.6 earthquake. It was followed by a second damaging event shortly after. The two events killed a total of 939 people.

The main source of traditional Pu'er tea, the forests surrounding Jingmai Mountain (普洱景迈山古茶林), have been inscribed as a UNESCO World Heritage site.

Lancang Lahu Autonomous County comprises five towns, nine townships and six ethnic townships.

A large portion of the population are of Lahu ethnicity, and Lahu language is one of the official languages in the county.

The Akha language, whose speakers are officially classified as Hani people, is also spoken in Lancang County. Ethnic Hani townships include Fazhan 发展河哈尼族乡 and Jiujing 酒井哈尼族乡 townships. Menglang 勐朗镇 and Huimin 惠民镇 were formerly ethnic Hani townships, but are now towns (镇).

The Bisu language is spoken in the townships of Zhutang 竹塘乡 (in Dazhai 大寨, Laomian 老面 village; see Laomian language), Laba 拉巴乡, Donglang 东朗乡, and Fubang 富邦乡.

Yi people also live in Lancang County, and are found in Qianliu Ethnic Yi Township 谦六彝族乡.