The purchase is set to boost Atkins' existing skills in aerospace and defence system engineering.
Nedtech posted an annual turnover of £3.5 million in 2006 with gross assets of £1.9 million.
Managing director of Atkins' design and engineering solutions business Ivor Catto said: "This acquisition enhances Atkins' capability to deliver high-end engineering and project management services to aerospace customers across Europe and positions us well for further growth in the sector.
"In particular it will enable us to respond to restructuring within Airbus."
The acquisition is conditional, with completion expected by the end of December 2007.