This article examines how the economic status of relatively ‘poor’ regions impacts upon the demands made by respective regionalist movements. Focussing on Corsica and Sardinia, it explores how regional movements frame their territorial demands in terms of socio-economic prosperity and inequalities, social justice and socio-economic colonialism, linking to the theory of ‘internal colonialism’ (Hechter, 1975). While scholarship has explored the ‘nationalism of the rich’ (Dalle Mulle, 2017, 2019), ‘bourgeois regionalism’ (Harvie, 1994) and the relationship between a region’s economic position and their position on the left-right spectrum (Massetti, 2009; Massetti and Schakel, 2015), ‘nationalism of the poor’ has received much less attention. We draw on in-depth qualitative analysis of political documents produced by regionalist political parties and civil society organisations for the period 1990-2018 to understand regional nationalism in two traditionally under-developed peripheral and insular territories. We argue that discursive elements related to internal colonialism, insularity and socio-economic inequalities are present in both cases, thus calling for further conceptualisation of the dynamics of stateless nationalism in ‘poorer’ regions.