The men targeted McGowans jewellers in New Kirk Road, Bearsden, East Dunbartonshire, at around noon yesterday.
A window was smashed and a quantity of rings and bracelets were taken by the pair in what Police Scotland said was a "high value" theft.
No exact figure was available.
The first suspect is described as around 6ft 2in, with a heavy build, and wearing a black balaclava. He was also wearing a dark jacket and grey jogging trousers.
The second suspect is around 5ft 5ins and was wearing a black balaclava, purple jacket and black trousers.
It is thought they made off in a white Nissan 4x4 car.