Chathannoor or Chathannur is a legislative assembly constituency in Kollam district of Kerala, India. As of the 2021 assembly elections, the current MLA is G. S. Jayalal of CPI.

Kollam district, is one of 14 districts of the state of Kerala, India. The district has a cross-section of Kerala's natural attributes; it is endowed with a long coastline, a major Laccadive Sea seaport and an inland lake. The district has many water bodies. Kallada River is one among them, and land on the east bank of the river is East Kallada and that on the west bank is West Kallada.