The council is to write to roads minister John Hayes calling for the stretch of road north of Shrewsbury to be included in the Government's Road Investment Strategy as part of its decision to back the Dual It campaign.
There was praise for the Star for spearheading the move for desperately needed improvements for the trunk road.
One of the major bottlenecks is the Oswestry bypass which regularly sees nose-to-tail traffic crawling from the Mile End roundabout to the Chirk bypass and beyond.
Councillor Claire Aspinall said she attended the public meeting in March when Mr Hayes came to the county to see the problems for himself.
"Dualling the stretch of the A5 is desperately needed," she said.
"There are of course the safety issues but we should also consider the economic benefits to dualling the road. Having a better road infrastructure would encourage more businesses to come to Oswestry."
Councillor Peter Cherrington said that the Oswestry bypass should have been a dual carriageway when it was first built.
"There are 10 million cars a year using the Mile End Roundabout at Oswestry. Surely that warrants improvements."
Former mayor, Councillor Paul Milner, said: "I would like to congratulate the Shropshire Star for launching this campaign.
"I would encourage everyone to sign the petition and get behind the Star. A dual carriageway would benefit everyone."
The town council is to ask Shropshire Council to also officially back the campaign and to write to North Shropshire MP Owen Paterson, a long time supporter of road improvements.
Councillor Chris Schofield said: "Mr Paterson has been calling for a dual carriageway since he was elected in 1997. The more big guns that support the call the better. This road is part of the Trans-European highway. Dualling it is vital for economic prosperity."
The town council is to have copies of the petition in the Guildhall for people to sign.
More than 3,000 people have signed the online petition and 130 have signed our paper petition forms. But we need many more to come forward and join the campaign.