Riga (Vidhan Sabha constituency) (Hindi: रिगा विधान सभा निर्वाचन क्षेत्र) is an assembly constituency in Sitamarhi district in the Indian state of Bihar.
As per Delimitation of Parliamentary and Assembly constituencies Order, 2008, 23. Riga (Vidhan Sabha constituency) is composed of the following: Riga, Bairgania and Suppi community development blocks.
Riga (Vidhan Sabha constituency) is part of 4. Sheohar (Lok Sabha constituency).
In the November 2010 state assembly elections, Motilal Prasad of BJP won the newly created 23 Riga assembly seat defeating his nearest rival Amit Kumar of Congress.