The winger will undergo surgery on the "serious injury" which he suffered in the 1-1 draw with Manchester United.
"Yannick Bolasie to undergo knee surgery after scans confirmed a serious ligament injury against Man Utd. Come back stronger, Yannick," the club tweeted.
| Yannick Bolasie to undergo knee surgery after scans confirmed a serious ligament injury against @ManUtd. Come back stronger, Yannick . pic.twitter.com/9zCPMqdw4D
— Everton (@Everton) December 5, 2016
Bolasie has played 13 times for Everton since his £25m move from Crystal Palace.