McNeill, dubbed Cesar, died at the age of 79 earlier this week and interim Hoops boss Lennon feels retiring his shirt number would be a fitting way to mark the club legend’s contribution.
Jozo Simunovic currently wears the No.5 while it has previously been worn by Joos Valgaeren, Gary Caldwell, Daniel Majstorovic and Virgil van Dijk since compulsory squad numbers were introduced in Scottish football.
Lennon said: “Why not [retire the shirt]? There will only ever be one Billy McNeill for me. So I think that is not a bad idea at all and hang it up there so everyone can see it for years on end.”
He added: “We are a club in mourning. On behalf of the players and staff, our thoughts go out to Liz [McNeill’s widow] and the family.
“Liz was just a rock for Billy over his whole life and the family gave him tremendous comfort, love, and care through his debilitating illness.
“He was the one, he was Celtic. We have lost him and it is a huge loss to the club.
“He was a leader of a great team and a leader of great men. I can’t put into words how big a loss he is to this club.
“When I was growing up, you hear stories of Lisbon Lions and they are without a doubt the greatest team in the club’s history.”
“Billy was tremendous support to me. Not only during the good times, but more importantly during tough times. He gave me a lot of advice. I couldn’t thank him enough for that.
“I saw Charlie Nicholas on tears on TV and I had a cry myself. I don’t think Billy realised how much he meant to so many people associated with the club. We have lost him, and it is a huge loss to our club.”