Shyamnagar (Bengali: শ্যামনগর) is an upazila of Satkhira District in the Division of Khulna, Bangladesh.

The main rivers here are: Raymangal, Kalindi, Kobadak, Kholpetua, Arpangachhia, Malancha, Hariabhanga and Chuna.

South Talpatti Island at the estuary of the Hariabhanga is notable.

The average literacy in the entire upazila is 28.1%, comprising 38% among males and 17.4% among females.

As of the 2011 Census of Bangladesh, Shyamnagar upazila had 72,279 households and a population of 318,254.

Shyamnagar Upazila is divided into 12 union parishads: Atulia, Bhurulia, Burigoalini, Gabura, Ishwaripur, Kaikhali, Kashimari, Munshiganj, Nurnagar, Padmapukur, Ramjannagar, and Shyamnagar.