Their parents of the 56 children from 16 countries had already become citizens themselves after undergoing the long wait for naturalization. Under U.S. immigration law, children under 18 whose parents become legal citizens automatically receive their own citizenship.
Thursday's ceremony came amid ongoing national controversy over immigration and citizenship issues and, most recently, the Deferred Action for Childhood Arrivals program.
The kids at the Los Angeles ceremony were not part of DACA, but have still been watching the political debate with increasing anxiety.
"It's been scary," said Josue Escobar, 17, of San Pedro. "We've been watching our backs, making sure nothing happens to us, we don't do nothing bad, you know?"
Josue and his little brother now feel like they have more freedom and their mom couldn't be more proud.
"It's a big thing for me," said their mother, Brenda Mina. "I'm a single mother. It's just me. This is my glory right now."