This article explores the spatial influences that shape the contemporary Czech party system and their consequences for the institutionalisation of the party system. First, the régionalisation of the party system is measured to identify the specific regional clusters of votes for individual parties. Second, after controlling for the impact of social cleavages, the independent effect of two macro-regions on the differences in voting decisions is analysed. In the case of Moravia, no such independent effect is evident. Conversely, in the formerly German-inhabited Sudetenland there is an effect on the vote in the case of two parties (KSČM and ODS). The historical reasons for this spatial regime are briefly discussed. Finally, the relative insignificance of spatial regimes in the Czech party system is explained with reference to its high degree of nationalisation (the level of spatial heterogeneity in regional voting results). The author employs spatial analytical techniques in the article, such as measures of spatial autocorrelation, the spatial regression model, and the Gini Index. The findings suggest that there is a high degree of spatial institutionalisation of the Czech party system and relatively insignificant contextual effects at the macro-regional level.