Stefan Damian Dragos, 28, allegedly provided the truck which was used to smuggle the group of migrants, who were found dead in a freight container on the back of the vehicle in October 2019, Italian police said in a statement on Saturday.
There was no immediate statement from the suspect or from any lawyer representing him. He was arrested in the town of Cinisello Balsamo, north of Milan, but police gave no further details.
The discovery of so many dead people - two as young as 15 - in the back of the truck on an industrial estate to the east of London shocked Britain and Vietnam. It also shone a spotlight on the illicit global trade that sends the poor of Asia, Africa and the Middle East on perilous journeys to the West.
Most of those who died were from Nghe An and Ha Tinh provinces in north-central Vietnam, where poor job prospects, environmental disasters and the promise of financial reward abroad fuel migration.
In January four men who admitted or were found guilty of manslaughter and immigration offenses were given long jail sentences.