The men in red, who were heavy favourites, got off to a great start in the second minute.
Vietnam had some chances in the first half, but coordination and luck were not on their side and the first half ended with a narrow 1-0 lead.
The struggles continued for Vietnam in the second half, as Laos stayed strong in defence, and even got dangerous from counters.
Vietnam doubled their lead in the second minute of added time. Substitutes Khuat Van Khang and Nguyen Quoc Viet combined to secure Vietnam's three points, with a pinpoint cross and finish.
With this result, Vietnam are currently in second place in Group B, behind rivals Thailand who won 3-1 against Singapore earlier.
Elsewhere in Group A, hosts Cambodia hammered Timor Leste 4-0 in their opening match, while another favourite, Indonesia, confidently won 3-0 against the Philippines.
Vietnam will play their second match of the group stage against Singapore on May 3.
