Chhatak () is an upazila of the Sunamganj District in Sylhet Division, Bangladesh. Its headquarters are in the town in Chhatak.
Chhatak is located at . It has 43,727 households and a total area 434.76 km<sup>2</sup>.
According to the 2022 Bangladeshi census, Chhatak Upazila had 85,413 households and a population of 445,797. 10.31% of the population were under 5 years of age. Chhatak had a literacy rate (age 7 and over) of 68.09%: 69.95% for males and 66.38% for females, and a sex ratio of 93.36 males for every 100 females. 60,902 (13.66%) lived in urban areas.
According to the 2011 Census of Bangladesh, Chhatak Upazila had 66,724 households and a population of 397,642. 115,129 (28.95%) were under 10 years of age. Chhatak had a literacy rate (age 7 and over) of 38.55%, compared to the national average of 51.8%, and a sex ratio of 1009 females per 1000 males. 50,678 (12.74%) lived in urban areas.
At the time of the 1991 Bangladesh census, Chhatak had a population of 273,153. Males constituted 51.05% of the population and females 48.95%. The adult (18+) population was 135,445. Chhatak had an average literacy rate of 24.5% (7+ years) compared with the national average of 32.4%. Religious affiliation was: Muslim 83.08%, Hindu 16.75%, Buddhist, Christian and others 0.17%.
Chhatak Upazila is divided into Chhatak Municipality and 13 union parishads: Bhatgaon, Chhaila Afjalabad, Chhatak, Chormoholla, Dolarbazar, Gobindganj-Syedergaon, Islampur, Jauwa Bazar, Kalaruka, Khurma Dakshin, Khurma Uttar, Noarai, and Singchapair. The union parishads are subdivided into 287 mauzas and 539 villages.
Chhatak Municipality is subdivided into 9 wards and 23 mahallas.