Internal migration has a negative direct effect on economic growth in Turkish provinces over 2008–2020, but produces positive spillovers to neighbouring regions, resulting in an overall insignificant total impact. Technological capacity influences regional growth only locally with no significant spatial spillovers, while human capital shows opposing direct and spillover effects that partially offset each other. Public investment stands out as a major driver of growth, generating strong positive direct effects as well as substantial aggregate impacts across regions. The analysis, based on a Spatial Durbin Model within an augmented Solow–Swan framework, confirms strong spatial dependence in growth processes and highlights the importance of spatially targeted regional development policies.