The Aim-listed PLC has acquired Link Maker Systems in a deal worth up to £4.5m.
Link Maker Systems provides a platform that “increases placement choice for children awaiting adoption”, improving collaboration between adoption agencies in England, Wales and Scotland.
The Bristol-based firm is a supplier to the Crown Commercial Service.
It had sales of £1.56m in the year to 31 March with EBIT of around £890,000, although Software Circle said its valuation was based on anticipated lower EBIT of £700,000.
The three shareholders will remain with the nine-strong company.
The deal involves an initial consideration of £3m with up to £1.5m in further payments if the business meets certain performance targets.
Software Circle CEO Gavin Cockerill, CEO commented: "What Link Maker do really matters and we are extremely proud to have the team join us as the second business in our Health and Social Care segment.
“Together, we believe we can make children's social care more efficient, more secure and more child focussed. We're looking forward to helping Andy, Craig, Linda and the team achieve the future aims of the business.”