Many state legislatures have adopted state ethics commissions over time. Beginning in the late 1960?s and early 1970?s, ethics laws, campaign finance reforms, and state ethics commissions diffused across states. With the adoption of both ethics commissions and ethics reforms, it has been taken as self-evident that these bodies have been adopted due to political scandal, that they reduce political corruption, that they increase public trust and confidence in government, and that they boost public approval of state political institutions. However, these claims have, in many cases, failed to be systematically and empirically examined. As a result, little scholarly attention has been paid to studying the determinants or effects of adopting these institutions. In an attempt to understand why states adopt ethics commissions, and the effects of doing so, the central questions that my dissertation will address are: Why do state legislatures adopt ethics commissions? And, does the adoption of these institutions have any effects on political corruption, trust and confidence in government, or public approval of state political institutions? I find that state ethics commissions are adopted in the wake of political scandal and because of the increasing need for administration of campaign finance laws. I also find that although state ethics commissions have no effect on corruption and trust and confidence in government, they do positively impact public approval.