Jens Stoltenberg has made a rare visit to the Former Yugoslav Republic of Macedonia, which is renewing its bid to join the alliance.
A dispute over the Former Yugoslav Republic of Macedonia's name is holding back the Balkan state's ambitions of both joining NATO and the EU.
Greece, which is a NATO member, objects to it shortening its name to simply "Macedonia" as it has a province with the same name.
But addressing the parliament in the capital Skopje, NATO Secretary General Jens Stoltenberg said that “membership is about much more than solving the name issue.”
“Allies are bound together not just by common interests but also by common values. And countries aspiring to join the Alliance must demonstrate that they share those values,” he stated.
Stoltenberg met with the Macedonian prime minister and defence minister.
The UN's mediator Matthew Nimetz proposed some alternative names that weren’t released to the media.
Nimetz has previously said that he doesn’t think it realistic not to include Macedonia somewhere in the name.
Many Macedonians insist they have the right to call their country "Macedonia", including a small group of protesters outside the parliament.
"We are here to send a message to Stoltenberg, that we do not want to change our constitutional name," said Solza Grceva, a former member of Macedonian parliament, said at the protest.
Correction: This story has been updated to clarify that Stoltenberg did not meet with Nimetz.