Recently, the notion of left-behind places and regions has gained ground in academic debates on regional inequality and changing electoral landscapes. This paper proposes an approach to conceptualising and measuring regional “left-behindness” in three Central Eastern European countries that goes beyond a dichotomous division of regions into “left-behind” versus “not left-behind”. It understands left-behindness as a multi-dimensional continuum, representing regional disparities in living standards and socio-economic opportunities. Our understanding of left-behind plades is based to a large extent on the current economic conditions of the regions and their dynamics, but goes beyond them to include a wider range of socially relevant aspects of the living conditions, including educational attainment, poverty, and the attractiveness of places to live. The paper proposes an approach to measuring regional left-behindness and explores how it explains voting patterns. Thus, the paper is motivated by the seminal arguments of the 'geography of discontent' debate. Its proponents have argued that rising support for populist, right-wing nationalist-conservative and anti-system parties is often closely linked to spatial patterns of regional inequality. This argument has been repeatedly tested in Western European countries, but has remained under-researched in Central Eastern Europe. Using our approach, we were able to confirm the validity of the "geography of discontent" as a central thesis for all three countries studied. The novelty and added value of this study is that it extends the understanding of left-behindness and voting. Our multidimensional approach to left-behindness allows for a comprehensive interpretation of spatial patterns of populist voting in Central Eastern Europe. The relationship between regional left-behindness and voting behaviour varies in strength across different countries. In Czechia, there are strong associations for the parties ANO and SPD, but not for the KSČM. In eastern Germany, the association between left-behindness and support for the AfD is weaker, as is the case in Poland for the PiS. Another contribution of the multidimensional concept of left-behindness is the finding that different dimensions of left-behindness have different electoral effects. There appears to be a systematic influence of economic prosperity and relative expansion, which primarily captures the contrast between metropolitan areas and their hinterlands on the one hand, versus the rest of the country on the other—not only in terms of economic prosperity and relative expansion, but also in terms of a significant social status hierarchy. Poverty, however, shows a less stable relationship.