Kim Zolciak is keeping things moving ... seen driving in Georgia in her first public sighting since her son’s arrest.

"The Real Housewives of Atlanta" alum was photographed behind the wheel in Alpharetta ... days after news broke that her 15-year-old son, Kroy Biermann Jr., had been arrested.

As TMZ previously reported ... KJ was arrested and charged with aggravated sodomy and aggravated sexual battery after a female classmate accused him of sexually assaulting her.

Kim has strongly defended her son ... telling TMZ the allegations are false and claiming he passed a polygraph test.

She added the alleged victim has made "similar allegations involving two other people, which raises serious concerns that deserve to be carefully examined."

Her claim about the alleged victim has not been verified.

For now ... Kim appears to be keeping things low-key as the case moves forward.