The men forced open the locked door of the Strath Bar, on Strathmartine Street, at around 2.30am on Saturday and demanded money from two female members of staff.
They then grabbed the till, as well as two collection cans and a handbag, before fleeing.
Officers have appealed for information following the incident, with one of the men described as being white, aged between 30 and 40 with a local accent and who was wearing a light beige canvas jacket.
The second man is white, aged in his mid to late 20s, about 5ft 8in with a skinny build and a local accent. He was wearing a dark, zipped hooded top.
The third man is also white, aged 30-40, with a short beard. He was wearing a light baseball cap, checked shorts and a blue/grey canvas jacket.
Detective Sergeant Lucy Cameron said: "Thankfully the two women, aged 33 and 61, were not injured but this was quite a frightening experience for them both.
"The men ran off with the pub's till, two collections cans and a handbag, so they would have been pretty obvious if seen by someone on the street at that time.
"Officers are checking CCTV and have been back in the pub and the street speaking to people in the area but we would also appeal to anyone who may have seen the men either hanging about the bar beforehand or maybe running off afterwards."