Dumki () is an upazila of Patuakhali District in the Division of Barisal, Bangladesh.
Dumki Upazila is divided into five union parishads: Angaria, Labukhali, Muradia, Pangasia, and Sreerampur. The union parishads are subdivided into 21 mauzas and 24 villages.
According to the 2022 Bangladeshi census, Dumki Upazila had 19,289 households and a population of 81,839. 9.14% of the population were under 5 years of age. Dumki had a literacy rate (age 7 and over) of 81.28%: 83.79% for males and 79.00% for females, and a sex ratio of 92.68 males for every 100 females. 19,550 (23.89%) lived in urban areas.
According to the 2011 Census of Bangladesh, Dumki Upazila had 15,542 households and a population of 70,655. 16,570 (19.94%) were under 10 years of age. Dumki has a literacy rate (age 7 and over) of 66.4%, compared to the national average of 51.8%, and a sex ratio of 1090 females per 1000 males. 12,200 (17.27%) lived in urban areas.