Honeyman Park, a 17-acre development off West Main Street in Armadale, will comprise a mix of two-, three-, four- and five-bedroom homes of 12 different types.
Of the 280 homes, a third have been designated to affordable housing.
First residents are expected to move in to the £72m development during June.
Avant Homes previously built a £21m, 110-home development in Armadale called Ellis Vale. Regional managing director Jim Wilkinson said: “Work is progressing well at Honeyman Park and we are looking forward to delivering a wide variety of quality new homes for everyone.
“As a multi-tenure house-builder, we want to create vibrant communities and make owning a new home as accessible to as many people as possible wherever they are on their home buying journey.”