City governor Nirat Pongsitthithaworn joined US ambassador Robert Godec to launch the Austin-Chiang Mai Sister Cities Initiative at One Nimman shopping mall.
The event was also attended by the US consul in Chiang Mai, Lisa Buzenas, who is a native of Texas.
Nirat said the initiative marked a new beginning for the friendship between Chiang Mai and Austin and a celebration of the 70-year relationship between the two cities.
As sister cities, Chiang Mai and Austin would strengthen bonds and benefit from educational exchanges and economic and developmental cooperation, he added.
Wednesday's celebration came after the governor signed a memorandum of understanding with Texas Mayor Kirk Watson in November to launch the sister cities initiative.
Nirat said the agreement would expand cooperation between the two cities in various areas while boosting friendship between residents of both.
According to the City of Austin website, the agreement will facilitate collaboration between the local governments of Austin and Chiang Mai, as well as promoting trade, investment and economic development for mutual benefit, and cultivating new educational and cultural connections.
Wednesday evening's event featured cultural performances and booths selling products from Thailand and the US. The US consul general also took part in a local cultural show along with Thai performers.