Barfoot & Thompson won the award over global giants including CBRE, Savills and Australia's 1st City.
In the 2016 year, the firm sold $10 billion of property, managed more than 14,000 properties and won Large Real Estate Agency of the Year at the REINZ Awards for Excellence, among other achievements.
"We are extremely proud to be recognised by our peers for the international standard of service our clients receive, something many home-grown businesses aspire to," Thompson said.
"New Zealand produces excellent business people, and I'm fortunate to be surrounded by people who are driven, ingenious and authentic," he said.
"This is because of where we come from, not in spite of it."