How much do the prospects of international recognition of a possible new state affect the domestic support for secession? To answer this research question, we adopted a most similar systems design and conducted a Web-based survey experiment in Catalonia and Scotland. Respondents were presented with plausible scenarios regarding the international recognition of a hypothetical independent state by other countries and were subsequently asked whether they would support a unilateral declaration of independence. The results show that the prospects of international recognition as a sovereign and independent state influence the degree of support for a unilateral declaration of independence in both cases. This effect was moderated by the intensity of nationalist sentiment and the motivations for independence. Respondents with more outspoken nationalist sentiments were only marginally influenced by these scenarios or treatments. Moreover, participants whose preferences towards secession were driven by ethno-political motivations were less influenced by international factors than those who wanted an independent state for economic or political reasons.