Officers say a man grabbed a 13-year-old boy around the throat during the incident in Dronfield.
The assault happened in High Street and police say the man went on to threaten and push the teenager.
A Dronfield Safer Neighbourhood Team spokesperson said: “It is believed the man thought the boy and his friends had been laughing at him.
“It is thought the man in the image may be able to assist with our enquiries, if you can identify him, get in touch.
“The incident happened at 3.40pm on March 31 and we have been following a number of lines of enquiry since.”
Contact PC Adam Stubbs, quoting reference 22*184515.
Facebook – send a private message to the Derbyshire police Facebook page
Twitter – direct message @DerPolContact
Website – use the online contact form
Phone – call 101.
You can also contact Crimestoppers on 0800 555 111.