Best known as Shaq, the former NBA player said in a Twitter message that he "made a new friend today" when he "called and apologized to Jahmel Binion."
The tweet calls Binion a "great dude."
O'Neal spokesman Rishi Daulat told The Associated Press on Wednesday that O'Neal wrote the tweet.
Binion has ectodermal dysplasia, which affects his face, teeth and hair. He tells MLive.com he was "confused" when O'Neal posted a picture on Instagram showing him making a face imitating Binion.
The post was later taken down.
The National Foundation for Ectodermal Dysplasias wrote an open letter Monday to O'Neal saying "bullying is never acceptable."