Sirkazhi () is a major municipal town in Mayiladuthurai district in Tamil Nadu, India. It is located from the coast of the Bay of Bengal, and from the state capital Chennai. Sirkazhi was a part of Thanjavur district until 1991 and has later been part of Nagapattinam district. The town covers an area of and in 2011 had a population of 34,927. It is administered by a second grade municipality. Sirkazhi is part of the Cauvery delta region and agriculture is the major occupation. Roads are the main means of transportation; the town has of district roads, including a national highway.