Police said the men — one believed to be in his late teens and the other in his 20s — approached the girl at about 6:50 a.m. at Geary Boulevard and Laguna Street, near the Japan Center shopping center.
The girl had been waiting at the northeast corner of the intersection for a bus to attend an extracurricular activity for school, police said.
The younger of the two suspects told the girl, “Show me the money,” while the other brandished a silver revolver with a brown handle, police said.
The men then fled with the girl's handbag, jewelry and cell phone, running west on Geary Boulevard, according to police.
The younger suspect was described by police as a black male wearing a baseball cap, a black jacket and dark blue jeans. The older suspect was described as a black man wearing an orange San Francisco Giants baseball cap, a silver Giants rain jacket, blue jeans and a white shirt.
The girl was not injured, and no arrests have been made in the case.