The firm, which has offices in Glasgow, was awarded the contract by North Ayrshire Council.
The work will see the creation of a new £10.6m primary school, Irvine East Primary, following the amalgamation of Broomlands Primary, Fencedykes Primary and Towerlands Primary schools.
The 56,564 sq ft two-storey school, being built on the site of the former Broomlands Primary School, will comprise 18 classrooms, a gymnasium, dining hall, outdoor playground and additional support learning facilities, such as a therapy and sensory room.
The school, designed by Glasgow-based JM Architects, will house 521 pupils and is due to complete in summer 2014.
Castlepark Primary School will receive a full refurbishment and extensions which will include a new nursery to replace the original Castlepark Community Nursery building, dining hall and classrooms. Woodlands Primary School is to receive an extension of its nursery building.
Eddie Carr, area director for Morgan Sindall in Scotland, said: “We always look to support the local communities in which we work. During this project we are hoping to employ two apprentices and graduates to work on the scheme, and to maximise our local subcontractor engagement.”