Children living away from their country of origin are "among the most vulnerable people on earth and this vulnerability is only getting worse," the report said.
Almost 50 million children worldwide currently are migrants, refugees or internally displaced persons (IDPs), according to a United Nations International Children's Emergency Fund (UNICEF) report.
"This is a conservative estimate," UNICEF emphasized. "More than half of these girls and boys fled violence and insecurity - 28 million in total."
Child migration has increased significantly from 2005 to 2015. Child refugees doubled to 8 million, 17 million are now IDPs, and "1 in every 70 children worldwide live[s] outside their country of birth."
"Children are dramatically over-represented among the world's refugees," UNICEF explained. "Children make up less than one-third of the global population, but they constituted 51 percent of the world's refugees in 2015."
Anthony Lake, UNICEF executive director, noted that conflict is a significant driver of migration.
"The number of child refugees jumped by roughly 75 percent between 2010 and 2015," he said. "It's no coincidence that the same time period saw 15 conflicts either break out or reignite."
The report also cited "climate change, economic crises, rising inequality and natural disasters" as causes of migration.
Migrants tend to move and find asylum within their region of birth - five in 10 of all migrants and nine in 10 of all refugees do so.
Turkey, Pakistan, Lebanon, Iran and Ethiopia currently have the highest number of refugees living in their borders.
Children living away from their country of origin are "among the most vulnerable people on earth and this vulnerability is only getting worse," the report noted.
They often fall victim to human trafficking and other forms of exploitation and abuse, while having limited access to healthcare, education and other social services.
Even upon reaching intended destinations, "refugee and migrant children disproportionately face poverty and exclusion at a time when they are in desperate need of essential services and protection."
"Wherever they are and regardless of their migration status, children have a right to be protected, to keep learning and to receive the care and services they need to reach their full potential," UNICEF stated. "Every child has the same rights, and they retain those rights no matter where they are. Fulfilling the rights of these children and their families is both a moral and a practical imperative."
The full report is available here. An executive summary is available here.