Heyside Post Office - at 8-10 Heyside in Royton - will close temporarily for an extensive refurbishment.
The branch will not be open during the work, which will begin on Thursday 30 January at 9.30pm.
It's expected the branch will re-open on Monday 24 February at 7.30am.
People wanting to use the post office during those times will be able to use other branches at London Road in Oldham or on Rochdale Road in Royton.
Angela Bettison, Post Office Area Change Manager, said: "We apologise for any inconvenience caused to our customers during the refurbishment.
"The safety of our customers is of paramount, therefore, to allow for the building work to take place, it will be necessary for the service to close temporarily."
