Since 1991, the Belgian Election Survey (organised by ISPO-KU Leuven) gauges perceptions of economic and cultural threat that are related to the presence of immigrants. A structural equation model (with scalar invariance) for Flemish and Walloon voters shows relative stability in the prevalence of negative attitudes towards immigrants between 1991 and 2014, notwithstanding a couple of mild fluctuations. Anti-immigrant sentiments do not display a clear-cut upward or downward trend since the early 1990s. A comparison between Flanders and Wallonia reveals regional differences in the evolution of ethnic threat perceptions. Remarkably, in both regions we find an unexpected yet sizable decrease in perceived ethnic threat between 2010 and 2014. This finding is furthermore corroborated by the yearly SCV survey.