Authorities say most of the suspects are from Dimmit County and all faced initial court appearances Friday in Del Rio.
A federal grand jury in Del Rio this week returned five indictments in the undercover investigation involving cocaine and methamphetamine suppliers.
The charges include conspiracy, possession with intent to distribute a controlled substance and possession with intent to distribute a controlled substance within 1,000 feet of a school.
Investigators say the sales allegedly took place near Central Elementary School in Carrizo Springs and Big Wells Elementary School in Big Wells.
The arrests were announced Thursday afternoon.