The man was attacked on Calder Street, near South Annandale Street, at around 4.35pm on Wednesday, by a man who verbally abused him as he walked past.
The victim was taken to the Victoria Infirmary for treatment to a number of stab wounds and was later released.
Police are appealling for witnesses in order to trace the suspect, described as white, in his 40s, about 6ft tall and of slim build. He has a gaunt appearance, short grey hair and was wearing a black jacket with puffy sleeves and thin material on the body.
Detective constable Peter McFarlane said: “The injured man was waiting to meet a friend when this man walked by him and for whatever reason took umbrage and lunged at him.
“He tried to push him off, however the suspect stabbed him and then ran off towards Cathcart Road.”
He added: “We are checking CCTV and speaking to people in the area but we know that at least two people stopped to intervene in the attack and then to assist the man.
“I am very keen to speak to them as they may have information that will assist our inquiry.
“Calder Street is very busy and we can see that from CCTV. It’s possible that people have seen the suspect round and about or may indeed have been approached by him.”
Anyone with information can contact police on non-emergency number 101.