Together they provide support for more than 400 children in vulnerable circumstances by funding places at both private and state boarding schools across the UK, a statement from the organisations said.
David Howarth, director of JET, said the move would formalise a working partnership between the two charities that had existed for several years.
He said they would merge their offices and five staff and move into the RWCF’s office in Cobham, Surrey. There would be no job losses, he added.
According to Howarth, the RNCF hoped to offer a total of 5 per cent more funding per year for the first two years than the two charities had managed alone, with the aim of increasing this as the profile of the charity grew.
"The JET has a good fundraising operation, while the RWCF operates with a significant endowment, so there is no current competition between the two. The hope is that it will form something greater than the sum of its parts," he said.
Sarah Mulligan, assistant director at JET, said it had not yet been decided whether the organisation would have a single chief executive. Howarth will work alongside RWCF director Christine Hughes during the merger, Mulligan added.
The two boards of trustees will be merged, with RWCF’s chair Colin Morrison becoming chair of the new organisation. David Ives, chair of JET, will become deputy chair.