The Scottish Council for Voluntary Organisations is making 23 redundancies.
The umbrella body, which employs 132 staff, said the major factor in the decision was an expected fall in income over the next year.
Of the 23 jobs that will go, 12 are specific posts, four are staff on short-term contracts that will not be renewed and one staff member is retiring and will not be replaced.
A further six posts will be lost under a merger of roles as some departments are restructured.
John Downie, director of public affairs at the SCVO, said it was not yet clear how much funding the SCVO would lose because it still had funding applications pending.
He said third sector organisations in Scotland were suffering from the Scottish government’s policy of not making any compulsory redundancies in the public sector.
"This means the job losses are being exported to the voluntary sector in Scotland," he said.
The redundancy process would be concluded by the end of March, he said.