UFC Fight Night: Walker vs. Zhang (also known as UFC Fight Night 257 and UFC on ESPN+ 115) was a mixed martial arts event produced by the Ultimate Fighting Championship that took place on August 23, 2025, at the Shanghai Indoor Stadium in Shanghai, China.
The event marked the promotion's second visit to Shanghai and first since in November 2017. It was also the first time since the COVID-19 pandemic that the UFC has returned to Mainland China. The promotion was originally expected to make their return to the location at in December 2023, before moving that event to Las Vegas due to undisclosed reasons.
A light heavyweight bout between Johnny Walker and Zhang Mingyang headlined this event.
A catchweight bout between former UFC Featherweight Championship challenger Brian Ortega and former UFC Bantamweight Champion Aljamain Sterling took place in a five round co-headliner. Originally slated as a featherweight bout, it was changed to a catchweight of 153 pounds after reports that Ortega had complications during his weight cut.
Shi Ming and Bruna Brasil were expected to meet in a women's strawweight bout at the event. However, the pairing was pulled in order to serve as the featured bout of the Road to UFC Season 4 semifinals event a day earlier.
A welterweight bout between Song Kenan and Kiefer Crosbie was scheduled for this event. However, Song withdrew from the fight for unknown reasons and was replaced by promotional newcomer Taiyilake Nueraji.
In addition, a middleweight bout between Michel Pereira and Marco Tulio was also scheduled for this event. However, Tulio withdrew from the fight for unknown reasons and was replaced by returning veteran Kyle Daukaus.
The following fighters received $50,000 bonuses.