Hanoi followed at VND6.42 million, and Ho Chi Minh City came third at VND6.39 million, according to the Citizen Living Standard Survey released by the General Statistics Office.
This means residents in Binh Duong had an average income 25% higher than the two biggest cities in the country.
Binh Duong is the industrial capital of Vietnam, with urbanization among the fastest in the country.
Other localities with a high average income of over VND5 million were Dong Nai, Hai Phong, Da Nang, Bac Ninh, Can Tho and Vinh Phuc.
Ha Giang recorded the lowest income at VND2.06 million.
The national average income was VND4.67 million per month, up 11.1% from 2020, with rises seen in both urban and rural areas, showing a post-pandemic recovery.
The average person spent VND2.8 million a month last year, down 3.3% from 2020.