Shocking video has emerged of a teenager being knocked out in a vicious one-punch attack in Surfers Paradise.

The video was shot about 3.15am today on Orchid Avenue and shows three men kicking the victim in the legs before he is punched to the ground.

9NEWS understands the victim was unconscious for a few minutes and was left bleeding from the head before being transported to Gold Coast University Hospital for treatment.

The man was attacked on Orchid Avenue this morning. (9NEWS)

Video shows the moment the man was knocked unconscious. (9NEWS)

The man was treated for head injuries but is expected to make a full recovery. (9NEWS)

The victim is understood to be an 18-year-old Schoolies reveller who was visiting the Gold Coast from New South Wales.

A friend has told 9NEWS the teenager was targeted after sticking up for a group of women who were being harassed outside a bar.