This study aims to identify planning techniques for a low-carbon green city. A total of 42 techniques were derived from the literature review and case studies and were organized into four categories: green spatial structure, green transportation systems, green energy, and green construction. Based on these results, 21 techniques were selected as priorities for introduction in Korea through an expert importance assessment and a cost–carbon reduction effectiveness analysis. The analysis highlights key directions for green spatial structure, including subdivision layout, securing green areas for carbon absorption, and considering compact and mixed land use as well as wind and microclimate conditions. For green transportation systems, priority techniques include introducing energy-saving transport modes, implementing transit-oriented development (TOD), and strengthening bicycle and pedestrian networks. In the green energy category, photovoltaic systems and geothermal heat systems were identified as major techniques. For green construction, energy-saving building techniques—such as high-performance windows, highly insulated and airtight materials, and daylighting—were also identified as significant priorities.