North Yorkshire Police said 16-year-old Robert was last seen at 2pm on Monday (January 6) at his family's address in Norton, near Malton.
A police spokesperson said: “Robert was last seen wearing a black Hoodrich coat, gray Nike tracksuit bottoms and gray and black trainers.
“Officers are currently carrying out an extensive investigation to locate Robert, and we have growing concerns for his welfare.
“Robert is known to frequent the York and Selby areas, so it is possible he may have traveled here.”
If you have seen him or have any information that may help, please call North Yorkshire Police on 101. If you witness it immediately please dial 999.
Please quote reference number 12250003473 when communicating this information.