The 21-year-old has broken through into Walter Mazzarri's squad this season and won his first cap for Italy last September.
He has made 35 appearances in Serie A this season, although more than half of those have come from the bench.
Despite not seeing regular first-team action, Insigne revealed that his future lies in Naples.
"I'll remain a Napoli player," he told Gazzetta dello Sport. "I have a long deal that will expire in 2017 and I'm happy to be here.
"Clearly, at the end of the season we will sit around a table to talk. At the end of the season there are always talks, but I'll stay at Napoli."
Insigne has found the net five times this season.