In each case, investigators say the man was inside a pickup truck and asked the girls for directions.
According to police, the first incident occurred on April 28, about 7am at a school bus stop near Avenue J and 8th Street. The next was on April 30 in front of Lamar High School at 7:25am. Police say a third girl was approached in the 1400 block of 7th Street at a school bus stop just a day ago at about 7am.
Detectives say the victims range in age from 12 to 18.
The suspect is believed to be a Hispanic man in his 30s with dark curly hair, possibly in a ponytail.
He's driving what the victims describe as possibly a Ford F-150, two tone, maroon on top, brown or gray on bottom. Investigators say the girls say there is a tool box in the truck bed.
Anyone with information about anything similar can contact the Rosenberg Police Department.