Land policies are commonly used to contribute to the implementation of the public policy of land-use planning (or spatial planning). In this sense, a spatially efficient land policy must allow the planning systems to achieve the land uses promoted by strategic planning. In addition to their role in land-use planning, land policies also contribute to public finance policies. From this perspective, a socioeconomically efficient land policy must allow public authorities to capture land value. The research presented in this article aimed to contribute to planning theory by initiating a reflection on the interactions between spatial and socioeconomic efficiency in land policy. In our view, to consider those two dimensions in a more integrated way can help in the development of the growing research field on land value capture. Our research is based on the general assumption that there are processes of mutual strengthening and blockages between spatial efficiency and socioeconomic efficiency in land policy. In order to test this assumption, an international comparison methodology was developed. In order to develop a robust methodological approach, our exploratory comparative approach is based on a theoretical framework that depicts an ideal planning system. This ideal planning system serves as a benchmark for two empirical case studies on Norway and Belgium. Through our research, we find evidence of the interdependency of spatial efficiency and socioeconomic efficiency. The results of the two case studies therefore indicate that our initial assumption is generally confirmed. However further investigations are needed to deepen our exploratory discussion of the topic.