The Real Madrid superstar was crowned the 2016 Ballon d'Or winner on Monday night, the fourth time he has won the award.
And United felt it necessary to praise their former player, posting an update on their Facebook page that read: "Congratulations to Cristiano Ronaldo... Ballon d'Or winner for an incredible fourth time."
Some supporters weren't happy to see the club saluting the Portuguese, despite the fact he achieved so much during his time at Old Trafford.
Ronaldo won three Premier League titles during his six years as a United player, while he also helped the Red Devils claim the Champions League in Moscow back in 2008.
One United fan blasted the club as "pathetic" for their nod to Ronaldo, while others suggested they should focus on praising the current members of their playing squad.