Barry, 60, flanked by her husband Grant Kerr, told reporters that it had been a tough decision to step down.
"Now it's time to do some other things. My husband Grant and I are looking forward to spending a few months of the year overseas.
"We have a bucket list as long as your arm."
She said her National colleagues were surprised when she told them she was leaving this morning.
But she wasn't a career politician and knew from the beginning she was in Parliament for "a good time, not a long time".
Barry was Minister for Arts, Culture and Heritage, Minister of Conservation, and Minister for Senior Citizens.
She cited the campaign to be predator-free by 2050 as one of the things she was most proud of, as well as raising awareness of elder abuse.
Another personal highlight was being responsible for the World War I commemorations as Arts, Culture and Heritage Minister.
"It truly was an honour unveiling the New Zealand plaques at many of the French and Belgium Western Front battlefields and reading the ode at the Menin Gate."
She said she it was a huge privilege and honour to be an MP, but it was a drain on one's time.
"Your life is not your own ... It's a huge amount of time and effort, as it ought to be, because it's such an important role. But now's the time to do some other things. "
Barry has had a relatively turbulent term, with former staffers accusing her of bullying and intimidating behaviour and of being asked to do National Party work - which would be illegal.
Barry denied any wrongdoing and said she was involved in two employment matters, which were settled confidentially.
A Parliamentary Service investigation largely cleared Barry, saying that her support staff had worked briefly on party or political matters, but these were "extremely immaterial".
The Herald also revealed that staff from three government departments who worked with Barry had raised concerns about her behaviour when she was a minister.
Barry said that she was never made aware of any formal complaints against her.
National leader Simon Bridges today thanked Barry for her service.
"She has been a valued colleague and friend. We know Maggie will continue to support us throughout the campaign."
He said she has been a great representative for the people of North Shore and a valuable member of the National Party caucus.
Bridges said: "We are brimming with talent and I have no doubt that we will see a vigorous contest for the North Shore seat."
Barry said she continued to hope that the voluntary euthanasia bill would be voted down next week, but if it passed and the issue went to a referendum, she would continue to campaign against it.
She did not have anyone in mind to succeed her in the North Shore seat, but that was up to the local delegates.
"It is an amazing seat and there's huge support there, and I'm sure it will be hotly contested."
Barry is the tenth National MP to announce they're leaving the party since it came into Opposition in 2017. This others are: Jonathan Coleman, Steven Joyce, Bill English, Chris Finlayson, Jami-Lee Ross, Nuk Korako, Amy Adams, Alastair Scott and Nathan Guy.
