From late 2010 through 2011, popular uprisings toppled authoritarian regimes in Tunisia, Egypt, and Libya. In each country, a key component of the new regime’s “founding moment” was the selection of rules for the first democratically elected assembly. This paper asks how the design of electoral systems affected the outcomes of the founding elections. We are interested in whether the rules of competition were consequential in determining winners and losers, and to the quality and trajectory of democratization. Our conclusions are based on analysis of district level results from the list proportional representation component of each election and on first person interviews with actors in who participated in the design of electoral rules.