O2 want to build four antennae and cabinets inside the clock tower at Barony Chambers in Kirkintilloch.
A spokesperson for the mobile phone company said: "The planning application is to put the mast behind the louvres on the clock tower, so there will be nothing visible to the naked eye.
"The mast is for our 3G network and it's going in there because we have identified a requirement for that service in the area.
"We recognise that putting structures on the street or green field sites can sometimes be off-putting for local communities therefore we try to find solutions to that where we can."
Barony Chambers, at Cowgate in Kirkintilloch, is a B-listed building and planning permission needs to be approved by Historic Scotland.
Leigh Johnston, Historic Scotland's senior inspector, said: "Historic Scotland has not received an application for a telephone mast to be incorporated into the steeple yet and would expect to be consulted should East Dunbartonshire Council be minded to grant permission.
"As a B-listed building it is important that any alterations are appropriate and do not unnecessarily diminish the historic character of the building."