The girl, named only as Pamela, had her first set of female triplets aged 15, having first given birth to a son when she was just 14.
All seven children were born prematurely but without any kind of fertility treatment.
While doctors say the three newborns and their mother are well, the case has sparked debate across Argentina.
In bars and cafes, as well as the letters pages of newspapers, there has been widespread criticism of Pamela's alleged promiscuity.
Pamela's family already receives help from the provincial authorities, which donated land and built them a house when the first set of triplets was born.
Pamela's mother, who cleans houses to support her daughter and rapidly increasing number of grandchildren, says they will now seek more assistance from the government for the new additions to the family.
Some Argentines are arguing that perhaps what Pamela needs is more advice on contraception.
The teenager, who will be 17 on Monday, comes from the remote town of Leones in the central Argentine province of Cordoba.