Holmes will receive $6.5 million for the three-year deal, Ian Rapoport of the NFL Network reported. The move comes three days after Holmes refuted a report via Twitter that he agreed to sign with Buffalo.
On Saturday, Holmes sent a thank you tweet to Raiders fans while also tweeting a shout-out to his new employer and its fans by writing: "What's up #BillsMafia"
The 6-foot-4, 210-pound Holmes had 14 receptions for 126 yards and three touchdowns in 2016 season -- his fourth year with Oakland.
An undrafted free agent out of Hillsdale College who spend his first two seasons with the Dallas Cowboys, Holmes established career highs with 47 catches for 693 yards and fourth touchdowns in 2014 with Oakland. His numbers diminished to 14 receptions in each of the last two seasons.
Holmes, 28, became expendable when the Raiders signed former Minnesota Vikings wide receiver/kick returner Cordarrelle Patterson earlier in the week.
In his six seasons, Holmes has career totals of 102 receptions for 1,462 yards and 12 scores.