The incidents all happened when the teens were walking home from school.
Investigators say a 15-year-old girl reported that one man tried to get her into his car as she walked along Walnut Street in La Habra on three consecutive days.
When she resisted the third time, he got out of his red Ford Mustang or Chevy Camaro and approached her.
Another 15-year-old reported a man in a car with the same description tried to pick her up on Greenwood Avenue on Monday.
In Aliso Viejo, a teen girl said a man tried to get her into his older model white Dodge van on Wednesday.