Beyond simple description, not much is known about voting for regional parties in Western Europe, despite their importance in many political systems. Certainly, efforts to explain systematically a voter's general preference for a regional rather than a national party are virtually nonexistent. This paper seeks to rectify that neglect, focusing on the Spanish case, where voting for regional parties is quite prominent. Following a brief description of the regional parties in Spain and some theoretical analysis from a comparative perspective, we propose and then test with recent survey data three different hypotheses about regional versus national party support. We find that certain sociocultural cleavages, plus economic issues, directly motivate regional vote intention in Spain. In addition, we conclude that political involvement in general and concern over the European Community in particular, indirectly influence regional-national party preferences. On the basis of these multivariate results, we formulate a two-equation model to account for regional party support.