A Ho Chi Minh City court gave eight years to Nguyen Hoang Phong Thien and Nguyen Nhan Hoang, identified as the leaders of the gang that robbed 24-hour convenience stores in the downtown area at midnight between May and June last year.
Six of their accomplices got two to seven and a half years. All of them are aged 17.
According to the indictment, they would walk into stores like Circle K, Ministop, Shop & Go, and Family Mart in Districts 3, 5, 6, 11, and Tan Binh, armed with knives and other sharp objects, pick up the goods they want and flee.
If any employee tried to stop them, they were willing to use the knives or grab bottles to attack the staff.
They were arrested in August last year and investigators said they had robbed goods worth VND8.3 million ($358).
The defendants' acts threatened the health and lives of other people, the court ruled.
The number of convenience stores in Vietnam increased by 21 percent year-on-year to 1,819 last year, a survey from market research firm Q&Me found. Most of them are in Hanoi and Ho Chi Minh City.
Among these, many are open 24 hours, with just one or two employees working in the late hours, protected by no guards.