The firm was ranked above 34 other finalists after employees answered questions across categories such as culture and values, learning and development, communication and co-operation.
Three other insurance companies - Southern Cross Medical Care Society, Vero Insurance New Zealand and New Zealand-owned FMG - joined AA in the finals.
Other winners at the black tie awards ceremony at the Langham Hotel in Auckland included the Electricity and Gas Complaints Commissioner in the small workplace category, Brother International (NZ) in the small to medium, and Mars New Zealand in the medium-large category.
The largest survey of workplace climate and employee opinion in the country, it uses confidential feedback from employees to rate the organisations they work for.
Now in its 12th year, the survey attracted record feedback, with more than 31,700 employees responding.