In a statement to The Associated Press on Wednesday, Theron's publicist said the actress is a "proud mom of a healthy baby boy named Jackson."
No more details were provided.
Theron is from South Africa. This is the actress' first child.
The 36-year-old won an Academy Award for her role as serial killer Aileen Wuornos in 2003's "Monster."
She was also nominated for an Oscar for 2005's "North Country."