The firm will design, build and maintain five schools across the far-flung islands of Lewis, Harris and Benbecula.
Farrans bid the job with fellow Northern Irish contractors, H&J Martin and Patton Group, and Scottish facilities management specialist FES, which will carry out the life cycle maintenance of the new schools expected to be worth £45m of the total contract sum.
The contractor saw off rival bids from Scotland’s big name contractors Morrison and Miller.
The schools will be a mix of primary and secondary schools and are predominantly new build with a total floor space of 225, 000 sq ft.
Sgoiltean Ura, a special purpose vehicle set up by the Scottish Western Isles council Comhairle Nan Eilean Siar, procured the work.