Celtic’s miserable title defence continued last Sunday when a 1-0 defeat at relegation-threatened Ross County left the Bhoys 18 points behind leaders Rangers.
Celtic have won the Scottish league for the last nine seasons but it looks increasingly likely that Steven Gerrard’s men will put a stop to their quest for a tenth straight top flight crown.
Lennon returned for a second spell as Celtic manager in February 2019 after Brendan Rodgers left for Leicester City, and the 49-year-old added two more league titles to the three he won during his first spell in charge.
In a statement on Wednesday, Lennon said: "We have experienced a difficult season due to so many factors and, of course, it is very frustrating and disappointing that we have not been able to hit the same heights as we did previously.
"I have worked as hard as ever to try and turn things around, but unfortunately we have not managed to get the kind of run going that we have needed.
"I have always given my best to the Club and have been proud to deliver silverware to the Celtic supporters. The Club will always be part of me. I will always be a Celtic supporter myself and I will always want the best for Celtic.
"I would like to thank so many people at the Club who have given me so much and I would also like to thank my family for their love and support. I wish the Celtic supporters, players, staff and directors nothing but success for the future."
