Due to financing limitations, city governments increasingly rely upon private sector finance to support the supply of social and technical infrastructure. Accordingly, developer obligations have become increasingly important in urban planning and in land and property development. Compared to the numbers of previous studies related to 'non-negotiable developer obligations' (N-NDOs), the studies related to 'negotiable developer obligations' (NDOs) are much more limited. Also, there is a lack of studies comparing their respective impacts. The aim of this article is to compare the impacts of N-NDOs and NDOs within the specific country context of Turkey. The findings of study demonstrate that efficiency of N-NDOs and NDOs is closely related to the balance between certainty and flexibility in planning and land development system, the degree of transparency and the level of accountability, and value capture capacity.