Shahzadpur (Bengali: শাহজাদপুর) is an Upazila of Sirajganj District in the Division of Rajshahi, Bangladesh.
As of the 1991 Bangladesh census, Shahzadpur has a population of 420452. It has 70998 households and a total area of 324.47 km². Males constitute are 52.05% of the population, and females 47.95%. This Upazila's eighteen up population is 197052. Shahzadpur has an average literacy rate of 24.8% (7+ years), and the national average of 32.4% literate.
Shahzadpur thana was established in 1845 and was turned into an upazila in 1982. Shahzadpur Upazila has 16 Unions/Wards, 226 Mauzas/Mahallas, and 279 villages. Shahzadpur is also a municipal town, consisting of 9 wards and 31 mahallas. The area of the town is 19.52 sq km. The town has a population of 65897; male 51.95% and female 48.05%. The density of population is 3376 per sq km. Literacy rate among the town people is 34.5%. The town has one dakbungalow.
Shahzadpur is emotionally connected with the fond memory of the Nobel-lauriete Poet Rabindranath Tagore, who used to stay here in connection with administration of his father's zamindary. He wrote a lot of verses while living here. His Kuthibari (revenue office) is still there like the other place, Shilaidaha in Kushtia district.