Political parties have increasingly relied on self-regulation efforts to promote ethical standards in office. The effectiveness of these initiatives remains an open question. We argue that the ability of ethics self-regulation to induce sustained change is a function of the response from politicians and voters. Without external enforcement mechanisms, acquiescence from MPs is crucial for the success of these reforms. In turn, if voters deem self-regulation as cheap talk, reelection-seeking officials have fewer incentives to comply. We explore these questions in a paired conjoint experiment with elected officials and voters in Portugal and Spain. The results show that political elites support and voters reward financial disclosures, lobbying registries, and sanctionary measures for MPs involved in corruption cases. Voters also reward term limits in party lists. The results reveal concrete steps for parties to raise ethical and transparency standards in public office.