"I'm impressed by the way New Zealand handled the terrorist attack in March and the way you stood together; the way you have stood up for ... tolerance, democracy, individual liberty."
Those were Nato's core values, he said.
"As long as we do that in New Zealand, in Norway and elsewhere, the terrorists will not win. As long as we are standing up for our values, they are losing and we are winning."
His comments come just days after two mass shootings in the US in which 31 people were killed.
One of the shooters made reference to the Christchurch terrorist, allegedly saying he was the inspiration for the attack.
Stoltenberg said terrorists may try to inspire each other – "but we just have to stand together and defy them".
Stoltenberg also welcomed New Zealand's commitment to contribute more peacekeepers to Afghanistan, specifically to bolster the role of women in peacekeeping situations.
Ardern said the New Zealand Defence Force (NZDF) would be creating up to three roles focused on woman, peace and security issues within Nato's mission in Kabul.
"These roles will contribute towards safeguarding the hard-won gains Afghani woman and girls have made since 2001."
But Stoltenberg would not say if he was disappointed in the Government's decision to withdraw Kiwi troops from Iraq.
He had previously requested New Zealand send more troops into the region.
But In June, Ardern announced New Zealand would withdraw its troops, mainly based in the Taji Camp, by June 2020.
"I welcome what New Zealand has done in the global coalition over a long period of time; training the Iraqi forces," Stoltenberg said when asked if he was disappointed with the Government's decision.
