In this study, we investigated the differential effect of regional economic prosperity on mean student cognitive achievement by analysing data from a “natural experiment” in Palestine. Its main regions, Gaza and the West Bank, inhabited by a population sharing history, culture and gene pool, were only recently separated, yet distinctively affected by geopolitical events. The “experimental group”, living in Gaza, suffered from an enduring politico-economic crisis treatment, while the “control group”, inhabitants of the West Bank, was exposed to a much shorter and milder crisis. As a manipulation check, we used economic data reported by Etkes and Zimring (2015), who uncovered a severe and lasting decrease in household welfare and labour productivity in Gaza. As dependent variables, we used achievement scores of TIMSS maths and science students, which displayed only negligible pro-West Bank, pre-crisis differences (maths: Cohen's d = −0.04; t = −0.56; science: d = 0.11; t = 1.48). This margin grew during the crisis (maths: d = 0.17; t = 2.65; science: d = 0.26; t = 4.25) and even more so in the post-crisis phase (maths: d = 0.38; t = 5.09; science: d = 0.46; t = 6.76).