Satkhira Sadar () is an upazila (subdistrict) of Satkhira District in Khulna Division, Bangladesh.
Satkhira Sadar is located at . It has 109,105 households and a total area 400.82 km<sup>2</sup>.
Satkhira Sadar Upazila is bounded by Kalaroa Upazila on the north, Tala Upazila on the east, Debhata and Assasuni upazilas on the south and Basirhat I and Baduria CD Blocks in North 24 Parganas district in West Bengal, India, on the west.
According to the 2022 Bangladeshi census, Satkhira Sadar Upazila had 135,412 households and a population of 522,964. 8.61% were under 5 years of age. Satkhira Sadar had a literacy rate of 78.06%: 80.72% for males and 75.40% for females, with a sex ratio of 100.30 males per 100 females. 163,454 (31.25%) lived in urban areas.
As of the 2011 Census of Bangladesh, Satkhira Sadar upazila had 109,105 households and a population of 460,892. 85,999 inhabitants (18.66%) were under 10 years of age. Satkhira Sadar had an average literacy rate of 56.51%, compared to the national average of 51.8%, and a sex ratio of 998 females per 1,000 males. 113,322 inhabitants, or 24.59% of the population, lived in urban areas.
At the 1991 census, Satkhira Sadar had a population of 344,444. Males constituted 51.3% of the population, and females 48.7%. This Upazila's eighteen up population was 176,670. The average literacy rate was 34.6% (7+ years), compared to the national average of 32.4% literate.
Satkhira Sadar Upazila is divided into Satkhira Municipality and 14 union parishads: Agardari, Alipur, Baikari, Balli, Banshdaha, Bhomra, Brahmarajpur, Dhulihar, Fingri, Ghona, Jhaudanga, Kuskhali, Labsa, and Shibpur. The union parishads are subdivided into 119 mauzas and 237 villages.
Satkhira Municipality is subdivided into 9 wards and 33 mahallas.
Local colleges include: