Even though most real estate developers in Thailand acknowledge the significance of sustainability in terms of increasing the value of the project, the complexity of the investment for sustainability discourages them from pursuing it due to the higher investment costs. This research aimed to estimate the magnitude of Responsible Property Investment (RPI) factors on the condominium value for a condominium in Bangkok. A Linear Hedonic Price Model was created from the data collected from 167 secondhand condominium units in Bangkok, and it was discussed so conclusions and recommendations could be drawn for concerned stakeholders. This research quantitatively assessed the impact of RPI on the value of real estate projects. It was found that RPI can contribute more than half of a condominium’s value. Four subgroups of factors, i.e., Mass Transit Accessibility, Sustainability Technology, Domestic Transportation Accessibility, and Building Environmental Impact, contributed 51.69% of all the model weights. The results give real estate developers and investors information about the linkage between developing condominium projects with RPI and the increasing value from the customer’s point of view. At the same time, designers and policymakers can use the results as a guideline for supporting sustainable development.