This study aims to move beyond the international economics literature, which largely addresses borders through external trade costs, customs regimes and migration policies. Instead, it seeks to conceptualise borders as active and constitutive elements of development processes. The relationship between borders and development is examined within the study through engagement with classical economics, modernisation theories, dependency and world-systems approaches, and critical border studies. It is discussed how borders operate as multidimensional economic and institutional filters that can both support development and deepen inequalities. It is argued that borders are not merely geographical or legal lines of demarcation, but regulatory economic and institutional mechanisms that shape the circulation of labour, capital and goods, as well as policy choices. The applied examples presented in a policy context further demonstrate that the relationship between borders and development is not unidirectional, but rather exhibits a context- and institutional capacity-sensitive, reciprocal and multi-layered structure.