The incident occurred during Tuesday’s 2014 World Cup Group D game, which Uruguay won to qualify for the last 16. Uruguay have three days to appeal against the decision.
Suarez has also been fined 100,000 Swiss francs (£65,680).
The ban is the biggest in World Cup history, beating the eight games given to Italy’s Mauro Tassotti for elbowing Spain’s Luis Enrique in 1994.
“Such behaviour cannot be tolerated on any football pitch and, in particular, not at a FIFA World Cup when the eyes of millions of people are on the stars on the field,” Claudio Sulser, chairman of the Fifa disciplinary committee, said in a statement.
The referee did not see Suarez bite Chiellini on the left shoulder, but Fifa ordered an inquiry straight after the match following protests by the Italian.
Suarez has now been found guilty of biting three opponents in his career. He was banned for 10 games for biting Chelsea’s Branislav Ivanovic during a Premier League match in 2013 and was also suspended for seven games for biting PSV Eindhoven’s Otman Bakkal in 2010.