Mokokchung is a district of Nagaland state in India. The town of Mokokchung is its headquarters. It is the home of the Ao Naga tribe. It covers an area of 1,615 km². It is bounded by the state of Assam to its north, Wokha district to its west, Tuensang and Longleng district to its east, and Zunheboto district to its south.

The physiography of the district shows six distinct hill ranges. The ranges are approximately parallel to each other and are aligned roughly north-east/south-west. The district lies between 94.29 and 94.76 degrees east longitude and 26.20 and 26.77 degrees north latitude. The entire district of Mokokchung is conveniently sub-divided into ranges. The main valleys are Tsurang, Changki and Milak Valleys. The district is agriculturally and industrially among the most progressive districts in the state, along with Dimapur and Kohima. Major agricultural regions are Changki-Longnak, Tsurang, Milak and Dikhu valley regions. Tuli-Milak region and Changki-Longnak valley are the major industrial areas.

According to the 2011 census Mokokchung district has a population of 193,171,roughly equal to the nation of Samoa.This gives it a ranking of 591st in India (out of a total of 640).Mokokchung has a sex ratio of 927 females for every 1000 males, and a literacy rate of 92.68%.

Christianity is the predominant religion with 95% of its population being Baptist. The district was the first to embrace Christianity in the later part of the 19th century and continues to be the Main Baptist belt of India. Impur, the centre of Ao Baptist Arogo Mungdang (ABAM), i.e. Ao Baptist Churches Convention, and the largest convention affiliated with the Nagaland Baptist Churches Convention, is located at the heart of the district.