Recently, the importance of green building certification in consideration of environmentally friendly factors is being emphasized more when constructing buildings in South Korea. The Green Standard for Energy and Environmental Design (G-SEED) is one of the strategies used by the Korean government to effectively reduce building environmental loads. However, due to the large investment needed to acquire green building certification, building owners, stakeholders, and designers often contemplate how to balance G-SEED certification benefits and the additional costs they involve. Therefore, the purpose of this study was to assess the benefits of G-SEED certification in terms of post-occupancy financial advantages through a comparative analysis of real estate prices of apartments in the Yeongnam area. All of the major factors affecting apartment real estate prices in South Korea were considered, and the real estate price difference between G-SEED certified and non-certified apartments was determined through a one-sample t-test. The results demonstrated that G-SEED certified apartment real estate prices were 9.52% higher than non-certified apartments. This study concluded that G-SEED certification–related investment is worth the additional cost as it increases the real estate value of a building.