The two brands have been locked in a long-running legal battle over trademarks for years, which had previously halted the Irish company's attempts to expand its restaurant chain into the UK and Europe.
Having previously lost a battle over the similarity between its name and the Big Mac, Supermac’s asked the European Union Intellectual Property Office (EUIPO) to rule on the issue.
The Irish firm won a partial victory in January this year, and last week McDonald's lost its exclusive claim to the “Mc” trademark on some of its food products within the EU following another ruling by EUIPO.
The decision means McDonald's now only has the trademark rights for the use of “Mc” on chicken nuggets and sandwiches.
Supermac’s managing director Pat McDonagh has said the latest ruling was a "victory for small businesses".
Speaking to the Irish Independent, he said: "This latest decision by the EUIPO shows that but just because McDonald's has deep pockets and we are relatively small, it doesn't mean we weren't going to fight our corner.
"The judgment by the EUIPO is an indication of how important the European institutions are to help protect businesses that are trying to compete against faceless multinationals.”
Mr McDonagh also said the company is hoping to expand overseas in the next 12 months.
"We are targeting the UK first and especially London and the greater London area, as there is a huge Irish market over there."
Supermac’s was founded by Galway businessman McDonagh in 1978, and is now the largest Irish-owned fast food restaurant firm in the Republic of Ireland and currently operates more than 100 restaurants there.
The menu features an array of fast food staples including burgers, nuggets and loaded fries.