An investigation into the Gay and Lesbian Equality Network shows that charity funds were used to support a political campaign.
Inspectors for the Charities Regulator found there was a culture within the organisation where high levels of trust were placed in staff members without the necessary oversight of financial dealings.
The report says company credit cards were used for personal spending, with the money subsequently repaid.
The report also found that over €50,000 in credit card transactions were not backed up by receipts or invoices.
GLEN is currently in the process of being wound down.
John Farrelly, CEO of the Charities Regulator, is encouraging other organisations to learn lessons from this report.
He said: "The lack of robust governance in oversight, can have a really bad effect on an otherwise vibrant charity.
"Make sure your that your charities are well informed and engaged, you need robust governance to ensure that your charity remains vibrant."