Galway County Council has been judged to be the worst local authority in the country in terms of transparency, while Galway City Council was judged the best.
Transparency International Ireland carried out tests on information available online and by making inquiries to the country's 31 local authorities.
The results showed a big disparity between Galway city, judged to the best with a 70% score, compared to Galway County which was bottom of the table at 17%.
TII used indicators such as whether information on councillors's expenses and register of interests, submissions on planning applications and procurement policy is available online.
There were also tests to see how local authorities responded to phone and email queries and whether they complied with the law on Freedom of Information requests.
The four Dublin local authorities were in the top seven, along with Galway City in first place, Monaghan in fourth and Meath in sixth.
Waterford City and County Council came third last, ahead of Wexford County Council.
In its assessment of Galway County Council TII found "multiple" planning applications missing reports of pre-planning consultations.
The council's financial statement had also not been updated since 2013 and it failed to give a decision on a Freedom of Information application concerning an ethics issue within the time required by law.