A flag celebrating and honouring the Armed Forces community will fly above Belfast City Hall for six days from Monday.
Unionist and republican benches were divided over the issue following the request from the Ministry of Defence.
The flag will be hoisted above locations including 10 Downing Street, Tower Bridge and the BT Tower in London and hundreds of sites around the UK.
A row erupted after a letter was sent to the council from the MoD asking if the annual event could be marked by flying the flag over Belfast City Hall for six days leading up to June 29.
It came as tensions were still high following a council decision to restrict the flying of the Union flag at City Hall, leading to months of unionist protests and rioting.
The Alliance Party backed the limited flying of the Union flag last December, but supported unionist calls to display the Armed Forces flag for six days, with the SDLP and Sinn Fein benches objecting.
The proposal was adopted with 27 members voting for it and 24 against.
It will now fly until Saturday.
The head of the armed forces General Sir David Richards said Armed Forces Day, which takes place on Saturday, was a chance for the whole of the UK to show its support for service personnel and veterans.