Police say that at around 9.45pm a male entered an off licence on Donegall Road.
He threatened staff with a knife before making off with a sum of cash and a quantity of cigarettes.
The female staff member who was in the store at the time was not injured.
The robber is described as being about 5ft 9”, slim build and wearing a grey hoody, jeans and sunglasses.
Detective Sergeant Wilson said: “I am appealing for witnesses or anyone with information about this crime to get in touch with us by calling 101, quoting reference number 1355 10/08/2018.
“Information can also be provided to the independent charity Crimestoppers on 0800 555 111 which is 100% anonymous and gives people the power to speak up and stop crime.”