The 125-pound title fight will take place at Honda Center in Anaheim, California.
Fighting out of Los Angeles, Dillashaw (16-3) has campaigned for the opportunity to move down in weight for the better part of a year. The UFC explored a potential flyweight title bout between Dillashaw and former champion Demetrious Johnson this year, but it failed to materialize.
Cejudo (13-2) dethroned Johnson via split decision at UFC 227 in August. The upset victory ended Johnson's record-breaking title reign of 11 consecutive title defenses. Johnson has since left the UFC to compete in Asia-based promotion One Championship.
A U.S. Olympic gold medalist in wrestling, Cejudo avenged a previous loss to Johnson from April 2016. He immediately expressed interest in facing Dillashaw, although it was always uncertain at what weight they would meet.
Several flyweights publicly announced their sudden release from the UFC earlier this week, casting doubt on the future of the division. By Thursday night, it was unclear whether the UFC 233 champion vs. champion title fight would be the final 125-pound championship bout the UFC promotes.