Housing is central in the reproduction of social inequalities. Beyond divides across populations, trends point to increasingly unequal housing‐market dynamics across space. Nonetheless, little systematic evidence exists on the spatial inequality of housing values. In this paper we address this through a detailed investigation of house‐value developments in the Netherlands over time and space. We draw on national registers including longitudinal and geocoded data for the entire housing stock over the 2006–2018 period. Spatial polarisation is examined across different scales at the national, provincial, and urban level. We further investigate how housing‐market inequality trends vary over time, particularly between periods of economic boom and house‐price increases or, conversely, periods of downturn. Our analyses expose a substantial and widespread trend of spatial polarisation. Rising spatial inequality between neighbourhoods is clearly apparent at the national level, within all but one province, as well as for 44 of the 50 largest municipalities. The polarising trend appears structural and pervasive. While boom periods saw the strongest increases, inequality levels, remarkably, remained stable or even saw continued increases over the period of declining house prices. These patterns of spatial polarisation in house values have fundamental societal implications towards uneven wealth accumulation and in amplifying socio‐economic cleavages across populations and space.