The Hoops manager has been found guilty of offensive language by the Scottish Football Association after he was caught by TV cameras verbally abusing St Mirren's Jim Goodwin
A tribunal found that the Hoops boss had breached part of disciplinary rule 203 in his use of offensive language against Saints skipper Jim Goodwin and, although no new sanction was imposed, the Northern Irishman had a suspended three-match ban against his name from last season which has been triggered as a result.
Lennon is now set to be in the stands for the games against Motherwell, Ross County and St Johnstone, although Sunday's clash with Inverness CT will not be affected as he has five days to appeal the sentence.
A Celtic club statement read: "Clearly we are extremely surprised and disappointed by [Wednesday]'s decision.
"Fundamentally the particular disciplinary system in place is absurd - a system where such a case can be brought on the strength of two 'complaints' from people totally unconnected to the match in question, while a fourth official overseeing the technical area during the match makes no mention of any incident to the SFA.
"Despite even supportive comments from numerous individuals including Jim Goodwin himself, this judgement has been made, something which we find quite astonishing.
"It is clear that this decision will have huge repercussions for the game in Scotland and we are sure Hampden Stadium will be a very busy place now every Monday morning."