Chang Rong Si Bridge (Thai: สะพานช้างโรงสี, RTGS: Saphan Chang Rong Si, pronounced [sā.pʰāːn t͡ɕʰáːŋ rōːŋ sǐː]) is a bridge and monument in the Rattanakosin Island area at a tripoint between Phra Borom Maha Ratchawang and San Chaopho Suea with Wat Ratchabophit Subdistricts of Phra Nakhon District, the historic centre of Bangkok.

The bridge was originally built for elephants that returned from war and was located near a rice mill, hence came the name "Saphan Chang Rong Si", which literally means "elephants' bridge at rice mill".

During the reign of King Chulalongkorn (Rama V), the bridge was restored by Prince Damrong Rajanubhab, the chancellor of the interior, in 1910.

[1] Chang Rong Si was listed as a registered ancient monument of Bangkok in 1988.

Originally, it was a Muslim merchant's department store named " E. M. Katib" selling European glassware, perfume, and crockery.