Some SOS Kinderdorf staff members allegedly knew about the sexual abuse and other violence but tried to cover up the accusations. The NGO came forward with some of its findings, and is investigating the issue.
Children and young people attending facilities and projects run by SOS Children's Villages (SOS Kinderdorf in the original German) have been subject to sexual abuse and violence.
The Austrian-headquartered charity went public with the findings on Thursday.
The incidents of abuse reportedly date back to the 1990s.
Incidents were said to have taken place at around 50 projects in more than 20 countries worldwide. Projects in Africa and Asia are thoughtto have been worst-affected.
SOS Children's Villages' managing director Elisabeth Hauser said the incidents amounted to "serious misconduct on the part of employees."
Members of the charity's leadership were allegedly aware of the incidents but were active in trying to cover up accusations, Hauser added.
The organization also uncovered signs that funds were mismanaged or misused.
The allegations came to light through an external review in November 2020. SOS Children's Villages said it had started an initial investigation three years earlier.
Hauser did not specify how many children had been affected or where the abuse took place, citing ongoing investigations.
The NGO was founded in Austria in 1949, following the end of World War II, to provide humanitarian and developmental care for children.
The charity is currently active in 137 countries worldwide. It runs community programs as well as operating children's villages for children without families. It employs around 40,000 staff and cares for over 1.2 million children and youth.
The NGO has set up an independent commission to look into the incidents. The commission will identify individuals to face further proceedings or criminal investigations.
The commission is also set to make recommendations for structural changes. It will present the results of the inquiry later next year.
The charity is reportedly setting up a victim compensation fund, reaching "into the millions" of euros.