The retired NBA legend has established his affinity with Town via the club's owner Kelvin Thomas, with whom O'Neal runs an internet radio station in the United States.
"I just wanted to wish Kelvin and all the Cobblers best of luck.
"I'm looking forward to coming to Sixfields at some point to see a match," O'Neal added.
A spokesman at Northampton said: "We are delighted to have the support of Shaq, and his support has created a lot of excitement.
"We have invited him to come to a Northampton Town game when he is next in England and we can't wait to see him at Sixfields wearing a claret shirt, cheering the Cobblers on."
- Telegraph