Bill Lewis, FBI assistant director in charge, said 64-year-old Walter Lee Williams was arrested Tuesday by Mexican authorities, The Los Angeles Times reported.
The FBI said authorities have identified at least 10 of the alleged victims, who are between 9 and 17 years old. Officials said many live in third-world countries.
Williams, named to the FBI's 10 most-wanted list this week, either traveled extensively or lived in places across Southeast Asia and Polynesia, the Times said.
A four-count federal indictment filed April 30 alleged crimes involving two 14-year-old boys Williams met online in 2010. He allegedly "engaged in sexual activity via Internet webcam sessions with the boys and expressed a desire to visit them in the Philippines to have sex," the FBI said in a statement.
Williams fled Los Angeles after he was questioned by agents, FBI spokeswoman Laura Eimiller said.
Williams taught anthropology, gender studies and history at USC, information on a university Web page said. The page since has been removed, the Times said.
Williams is a Fulbright award winner who received the USC General Education Outstanding Teacher Award in 2006.