The Partenopei are third in the table and sit 12 points behind league leaders Juventus, but Maggio says that they must keep believing with 18 games of the season left to play.
"Twelve points behind the leaders is a lot," he told Radio Kiss Kiss. "But in football you can never say never.
"Sure, at this moment, Juventus look unstoppable. And looking at it Roma look like the team we can catch.
"There are obviously fewer points between us and the Giallorossi, but we can't give up."
Napoli host AC Chievo Verona in Serie A on Saturday.