Office buildings constitute a significant proportion of the non-residential building stock. In recent years, various rating tools have been developed to foster green office building development. The Green Building Council of Australia (GBCA) has developed the Green Star - Office rating tools for this purpose. There are an increasing number of stakeholders adopting these tools to showcase their efforts in sustainable development. This research focuses on the challenges and barriers in obtaining GBCA ratings in Australian Office buildings. To accomplish this, the scoring sheets from the rating of 264 certified office buildings were collected and critically analysed. The findings indicated that credits related to the attributes of innovation, ecology and energy are comparatively difficult to achieve. It was also found in this study that a large number of projects did not apply for the specific credits of refrigerant global warming potential, re-use of façade, topsoil and fill removal from site, and individual comfort control. This study provides a useful reference to both the property developer and the Green Building Council of Australia for green building developments in the future. In particular, the findings provide useful inputs to the development of the next generation of green building rating tools.