The construction industry is an enormous economic sector with a profound economic, social, and environmental impact. The building sector is responsible for one-third of total energy consumption and, notably, construction activities account for 39% of the total carbon emissions in the world. Therefore, nowadays, the promotion of green building concepts is essential for all countries. Typically, the sustainability level of a building is evaluated by specified certification systems through rating assessment tools. The development of national assessment tools is necessary for the developing world due to environmental, social, and economic issues; consequently, a national assessment tool adopted under specific local conditions would provide a more precise assessment. This paper analyzes the rating system of BREEAM, LEED, CASBEE, and Green Globes certification systems and discusses their adoption with assessment measures for the existing buildings in Kazakhstan’s reality. The following main criteria were discussed during six roundtable sessions: sustainable site and landscape, energy and carbon footprint reduction, water and wastewater management, indoor environmental quality, sustainable building materials, commissioning, and maintenance. A set of assessment criteria and measures were suggested, and 43 existing buildings were assessed. Only eight buildings reached a high rating level. The “sustainable site and landscape” and “indoor environmental air quality” categories were the categories with the highest scores; otherwise, “energy and carbon footprint reduction” with “water and wastewater management” had the lowest average scores. One of the buildings was evaluated separately by several experts to check the consistency of the suggested assessment measures. This evaluation also provided insight into how the assessors’ knowledge and experience may change the overall rating scores obtained. The most critical issues for the existing buildings in Kazakhstan’s reality were discussed. Despite the widespread adoption of green certification methodology, the application of global certification systems in Kazakhstan remains complicated due to the lack of knowledge and limited awareness.