Planners, environmentalists, architects, engineers, policymakers and economists have to work together to ensure that planning and development can meet our present needs without compromising the ability of future generations. This collaboration was the aim of the 12th International Conference on Sustainable Development and Planning, from which the papers in this volume originate. Problems related to development and planning, which affect rural and urban areas, are present in all regions of the world. Accelerated urbanisation has resulted in the deterioration of the environment and loss of quality of life. Urban development can also aggravate problems faced by rural areas such as forests, mountain regions and coastal areas, amongst many others. Taking into consideration the interaction between different regions and developing new methodologies for monitoring, planning and implementation of novel strategies can offer solutions mitigating environmental pollution and non-sustainable use of available resources. Energy-saving and eco-friendly building approaches have become an important part of modern development, which places special emphasis on resource optimisation. Planning has a key role to play in ensuring that these solutions, as well as new materials and processes, are incorporated in the most efficient manner. The included papers feature new academic findings and their applications in planning and development strategies, assessment tools, and decision-making processes.