Although the concept of Green Building is popular in other countries, it is not yet so in Sri Lanka as no clear identification of the transaction cost of green buildings has so far been made. Given the expanding scope of construction of office buildings in Sri Lanka, it has become important to differentiate between the transactions costs of green buildings from those of conventional buildings. Hence this research is aimed at studying the transaction costs of green office buildings in Sri Lanka. A literature synthesis was carried out to learn about the green building concept and the benefits of green buildings. Identification of the transaction cost components was done through three preliminary interviews and two case studies conducted through semi structured interviews that were aimed at comparing the cost components of each building type with those of the other type. The findings revealed that the transaction costs of green buildings in Sri Lanka relates to costs incurred for preliminary studies, managing the designs, gaining knowledge on green certified material, technical advice, documentation and commissioning for LEED certificates and quality checking by obtaining the services of green consultants. Hence, the state agencies need to ensure that green material is available at discounted prices, take steps to present awards to professionals involved in green building and conduct seminars for the benefit of these professionals. It is also recommended that the Green Building Council should lower its commissioning fees to encourage the developers to obtain green certificates so that the concept of Green Building in Sri Lanka is promoted
