Law lords rejected claims by the city council that 2500 claimants were not eligible for substantial pay-outs because their jobs were transferred to arms length external organisations set up by the local government authority.
Instead the Court of Session in Edinburgh has ruled in favour of female staff - cleaners, cooks, home helps and others - now working for organisations such as Cordia (Services) LLP which was set up five years ago.
Carol Fox of Edinburgh law firm Fox and Partners, welcomed the 40-page written judgement by three law lords - Lords Brodie, Drummond Young and Phillip.
She said Glasgow City Council had argued the claimants could no longer compare themselves with male workers who continue to be employed by the council.
Ms Fox said it was a deliberate strategy by the councl to avoid responsibility in an ongoing row over equal pay and said it had now been rejected by the "highest court in Scotland."
The legal battle is complex and there are two other appeals outstanding, but yesterday's decision keeps claimants on track in their fight for significant pay outs.
The 2500 female workers will now join 3000 others who are taking the council to an employment appeal tribunal (EAT).
Their lawyer warned the final settlement could be "multi-million".
Ms Fox said: "We are delighted to have yet another decision in support of our claimants.
"This means that these 2500 claimants who were subject to TUPE transfers to ALEOs will join the other 3000 claimants still working for Glasgow and will proceed to the EAT together.
"This sends out a very important message to public authorities that it is not acceptable to set up complicated organisational structures in order to escape equal pay liability."
Ms Fox today called on council bosses in Glasgow to end their objections and agree settlements before 2015, the 10th anniversary of the campaign to end pay inquality for public sector workers.
However, council chiefs played down the significance of the court judgment and point to the outstanding appeals.
A spokesman said: "The employment tribunal ruled earlier this year that Glasgow City Council's pay and grading structure is valid and not discriminatory.
"This ruling absolutely does not make it any more likely that Fox and partners will win their appeal against that very clear judgement."
English councils have settled claims while in Scotland private sector lawyers and unions are now working together in an attempt to reach cash settlements for all outstanding claims.