Relative PR will be headquartered in Edinburgh and also operate out of Inverness, with the aim of helping family-owned enterprises grow and future-proof themselves.
The agency will be based in Muckle’s offices and initially supported by Muckle’s 11 employees, with plans to hire direct recruits.
It will offer strategic comms advice to family boards and management teams, as well as practical and tactical support to help deliver PR programmes.
"Many family-owned firms that have passed through the generations are embracing change and understand the need to compete with emerging brands," Nathalie Agnew, founder and managing director of Relative PR and Muckle Media, said.
"We will work with family-owned businesses to help successfully manage their public relations and wider communications to ultimately maximise their market share. These businesses are the lifeblood of the UK economy, with two-thirds of firms in the UK family-owned, generating more than a quarter of UK GDP."
Agnew told PRWeek the agency wanted to open a family-owned specialist because staff had found working with these clients "really rewarding".
She added: "We often get a higher level of buy-in to communications from boards and family members and we can see the results of our efforts quickly. As the world’s first consultancy specialising in family-owned brands, we look forward to helping build and future-proof their stories, combining heritage and history with modernisation."