17-year-old Lake Reynolds is being held at Cherokee Adult Detention Center on Friday on an $11,200 bond.
There is no indication whether Reynolds has an attorney.
A Cherokee Sheriff's Office spokesman says Reynolds, a junior at Woodstock High School, is accused of posting a message on Twitter on Thursday night.
The spokesman says the posting said, "Planning on pulling a Columbine tomorrow guys, be prepared!"
The message appears to be in reference to the 1999 Columbine High School massacre, which resulted in 13 deaths before the two shooters killed themselves.
Sheriff's spokesman Jay Baker says Reynolds admitted to the tweet after the unarmed student was pulled out of class.