Kumarkhali (Bengali: কুমারখালি) is an upazila of Kushtia District in the Division of Khulna, Bangladesh. It is famous for the Shelaidaha area, where the poet Rabindranath Tagore spent a considerable time of his youth.

Kumarkhali is located at 23°51′15″N 89°14′30″E / 23.8542°N 89.2417°E / 23.8542; 89.2417. It has 79,008 households and total area 258.18 km.

It is bounded by Pabna Sadar Upazila and the Padma River on the north; Shailkupa Upazila on the south; Khoksa Upazila on the east; and Kushtia Sadar Upazila on the west.

As of the 2011 Census of Bangladesh, Kumarkhali upazila had 79,008 households and a population of 328,457. 70,884 (21.58%) inhabitants were under 10 years of age. Kumarkhali had an average literacy rate of 45.3%, compared to the national average of 51.8%, and a sex ratio of 1009 females per 1000 males. 21,914 (6.67%) of the population lived in urban areas.

At the 1991 Bangladesh census Kumarkhali had a population of 269,008, of whom 133,845 were aged 18 or older. Males constituted 51.77% of the population, and females made up 48.23%. Kumarkhali had an average literacy rate of 24.9% (7+ years), against the national average of 32.4%.

Kumarkhali Thana was formed in 1855 consisting of 13 parganas and it was upgraded into a Sub Division of Pabna District in 1857. In 1871 Kumarkhali Sub Division was abolished and it was included in Kushtia Sub Division under Nadia District. Kumarkhali Thana was turned into an upazila in 1983. Besides, Kumarkhali Municipality, formed in 1869, is one of the earliest municipalities of the undivided Bengal.

The upazila is divided into Kumarkhali Municipality and 11 union parishads: Bagulat, Chandpur, Chapra, Jadu Boyra, Jagannathpur, Kaya, Nandalalpur, Panti, Sadaki, Sadipur, and Shelaidaha. The union parishads are subdivided into 187 mauzas and 201 villages.

Kumarkhali Municipality is subdivided into 9 wards and 17 mahallas.

• Akbar Hossain, novelist, was born in Kaya village.

• Upazilas of Bangladesh
• Districts of Bangladesh
• Divisions of Bangladesh