Two members of staff were threatened with a handgun at Sunshine Grocers, Carntyne Road, around 5.45pm yesterday.
The gunman demanded money, but the 57-year-old shopkeeper and 48-year-old colleague defended themselves.
The suspect ran off empty handed towards Edinburgh Road.
He is described as white, 20-22, 5ft 8in and of skinny to medium build. He was wearing a grey hooded top and bottoms with red drawstrings, white trainers and a balaclava.
Detective Sergeant Roland Craig said: "Thank- fully the men were not injured, however it was very frightening for them."