Jones, a two-year starter, led Ole Miss with 75 tackles last season.
The Tuscaloosa, Alabama, native will be immediately eligible with two years of eligibility remaining.
"We are thrilled to add Jacquez to our team," Kentucky coach Mark Stoops said in a statement. "He's an experienced playmaker who has been a great leader in our league."
Jones is the second former Power 5 starter to transfer to Kentucky this offseason.
Wan'Dale Robinson, who led Nebraska with 51 receptions in eight games last season, announced in January that he was headed to Lexington. Kentucky also added former Penn State backup quarterback Will Levis in February.