Rosie Daniels and Catherine McMorrin have been appointed as investment directors in the company's Edinburgh office.
The firm has also recently appointed Douglas Spence, who will join from Standard Life Wealth in October, as investment director.
The Williams de Broe team in Scotland now totals 30, which includes the staff that the company lured away from Barclays Wealth to launch its Edinburgh private client business in 2008. The team is led by Murray MacKay, a former director at Barclays Wealth in the capital.
Philip Howell, chief executive of Williams de Broe, said: "We are delighted that further high-calibre professionals such as Rosie and Catherine have joined our growing team in Scotland. It is a clear endorsement of our approach to combine a personal service to clients with investment excellence."
Part of the Evolution Group, Williams de Broe has 5.8 billion funds under management for private clients and employs 290 staff across the UK.
The wealth management and private banking market has become increasingly crowded in Scotland with the likes of Bank of Scotland, Hambros, Rathbone Brothers, Rensburg Sheppards and Quilter also competing for business.