Electoral systems that are categorized in three general groups, Majority-Plurality, Proportional and Mixed systems, have different effects on political stability. An electoral system can affect differently the political stability in different circumstances. But the important point in studying the effects of electoral systems on political stability is that there is no direct relation between the two variables, so it is necessary to consider some intervening variables to explain their relation such as party system, parliament combination, government combination, political legitimacy, political culture, etc. Electoral system affect on these elements and in fact the changes occurred in these intervening variables affect the political stability/instability.

In this dissertation, the meaning of electoral system is the method of translating votes to seats, and the meaning of political stability is the relative absence of some instabilizer events that challenge the political power or political structure peacefully or hostile. In this thesis I have examined the kind of effects that electoral systems leave on political stability with considering those meanings noted above.    

For securing political stability in Iran, I have suggested Mixed system for electoral system reform with considering it’s particular political, social and cultural circumstances.

Electoral System, Political Stability, Party System, Parliament, Cabinet, Political Culture.