The 24-year-old victim suffered a double fracture to her cheekbone, a fractured nose and damage to her eye during the incident outside the Prince of Wales pub at Mill Hill in Leeds city centre.
She underwent surgery is continuing to receive medical treatment for her injuries.
The woman was struck in the face by a chair that was thrown during a fight involving a large group of men at around 11.30pm on Friday, June 5.
Police are now urging anyone with information about the suspect who threw the chair to come forward.
Detective Constable Lucy Hooker, of Leeds District CID, said: “The victim was very seriously injured and is still receiving treatment and it is vital that we trace the person responsible.
“The suspect was wearing a t-shirt with a large number three on the back and on the sleeve.
“We have been carrying out extensive enquiries into this incident over the last four months but have not yet been able to identify the man.
“I would ask anyone who thinks they know who it might be to contact us immediately.”
Call police on 101 or Crimestoppers anonymously on 0800 555 111.