The 41-year-old added that he has talked about such issues with his players before and claims that everyone in his squad respects one another.
"I have a zero tolerance rule," he is quoted as saying by the BBC. "I have spoken to the players about this before. We are an open club and we have been since the club was formed 125 years ago.
"Any sign of any sort of racism against colour, religion, background will be an instant sackable offence.
"I don't have to really speak to my players about that. The spirit and respect they have for each other is tremendous but they have been made well aware of that before.
"There is no place for that [discrimination] in the game and there never should have been. At this club we see everyone as equal and all I see are footballers and men and we treat them that way."
Lennon was appointed the Celtic manager in 2010.