The pay-per-view event will take place at the Mandalay Bay Events Center. UFC officials announced the middleweight bout Tuesday.
A former standout on "The Ultimate Fighter" reality series, Hall (8-4) ended an 0-2 skid in the Octagon with a TKO win over Chris Leben at UFC 168 in December. The New York native opened his UFC career in 2013 with back-to-back split-decision losses.
Santos (9-2) is coming off a first-round TKO win over Ronny Markes at a UFC Fight Night event in March. The Brazilian middleweight is 1-1 since signing with the UFC last year. He suffered a submission loss to Cezar Ferreira in his debut in August.