Runnisaidpur Assembly constituency is an assembly constituency in Sitamarhi district in the Indian state of Bihar.

As per Delimitation of Parliamentary and Assembly constituencies Order, 2008, 29.

Runnisaidpur Assembly constituency is composed of the following: Runni Saidpur community development block; Gaura, Mohini, Pandaul Buzurg, Bath Asli and Kauria Raipur gram panchayats of Nanpur CD Block.

[1] Runnisaidpur Assembly constituency is part of 5.

Sitamarhi (Lok Sabha constituency).