Justin Corsbie, 15, was last seen on Tuesday at Fulwood Academy, at around 5.15pm.
He was seen wearing a full, dark navy, Nike tracksuit with black Nike trainers and is believed to be frequenting the New Hall Lane area.
A police spokesman said: We are concerned for Justin’s welfare - if you have seen him, please contact us immediately.
"Furthermore, we would urge Justin, if he sees this appeal, to contact us to let us know he is safe."
Anyone with information, please contact police on 101, quoting log reference LC-20180911-0976