Lennon, who celebrated his fifth championship success at the weekend, is believed to be keen on a coaching career in England.
Lennon told the club’s website: I feel it is right to go out on a high given that we have just secured the league title for the second year running.
“Obviously having been with the club for so long, it will be a real wrench to leave, but I have thought long and hard about this decision and believe that it is the right one.”
Lennon added: “I have enjoyed my time at the club immensely.
“I have worked with two fantastic managers in Gordon Strachan and Martin O’Neill, enjoyed working with some quality players and had a great relationship with the Celtic Board and all the staff at the club.
“I would also like to thank the Celtic fans for their support. I have enjoyed a good relationship with supporters and sincerely appreciate the backing which they have given me over a number of years.
“This season has been particularly pleasing, having won the Championship, making the Scottish Cup final and obviously getting to the last 16 in the Champions League.
“It was a boyhood dream to play for the club I loved – I am very proud to have achieved this and played for Celtic for so many years and clearly, when Gordon Strachan made me captain of the club I was, of course, extremely honoured.
“I look forward to joining my team-mates and the manager in lifting the SPL trophy on Sunday. Great credit should go to the manager and his staff for all they have done over the past two years.
“We still have a good bit to do before the end of the season and I will be doing all I can to make sure we bring the Scottish Cup back to Celtic Park.”
Lennon joined Celtic from Leicester City in December 2000 for £5.75m.
