Petrography has been used by geologists to investigate rocks for over 150 years. More recently, petrographic techniques have been applied to the investigation of a wide range of construction geomaterials, most notably building stone, aggregates, concrete and mortar. The service life performance of buildings and infrastructure assets is dependent on good design and specification, the availability of high-quality construction materials, good construction workmanship and adequate maintenance. This paper reviews the state of practice for the petrography of geomaterials, as applied to construction projects worldwide. Petrographic methods and standards specific to geomaterials are introduced. Application of the techniques at various stages of the life cycle of structures is discussed including resource assessment, quality assurance, condition assessment, forensic engineering of failures and conservation of historic buildings. The contribution of petrography to sustainable construction is also discussed.