Garden Grove resident Cody Johnson, 47, is accused of molesting the girl from 1991 through 1998, beginning when she was just 5 years old.
The alleged victim contacted authorities after learning Johnson was working as a bus driver for the Garden Grove Unified School District. Before that he worked in the school district's food services division.
Investigators are concerned there may be more victims.
If you have information related to the case, call the Orange County Sheriff's Department at (866) TIP-OCSD.