Thanon Nakhon Chai Si (Thai: ถนนนครไชยศรี; pronounced [tʰā.nǒn ná(ʔ).kʰɔ̄ːn t͡ɕʰāj sǐː]) is a khwaeng (sub-district) of Dusit District, in Bangkok, Thailand.

The 3.185 km (2.0 mi) long road runs from the east in Phaya Thai District, entering Dusit area before ended up at Payap pier by Chao Phraya River.

Yothinburana School used to be situated at Kiak Kai (termination of Samsen road) and moved out in 2008 because of construction of new parliament house (Sappaya-Sapasathan).

[2] (except military bases) Nakhon Chai Si, Samsen, Rama V, Thahan, Thoet Damri and Pradiphat roads are the main thoroughfare of the area.

Thanon Nakhon Chai Si is served by Chao Phraya Express Boat's four piers: Payap (N18), Irrigation Dept.