Lobbying disclosure rules are discussed in many countries as means to increase transparency and curb conflicts of interests of politicians, but often face staunch opposition from policy-makers. Even though public support is important for implementing major transparency reforms to overcome political opposition, we know little about whether voters actually support increases to disclosure and transparency. We use a cross-country conjoint experiment administered in Germany and the United Kingdom to investigate the effect of rule strength, institutional coverage, and sanctions on popular support for regulations on lobbying disclosure, transparency of outside income, and limits on revolving door. Moreover, we investigate how lobbying disclosure rules affect vote choice and political trust. The results have important implications for the design of accountability and transparency mechanisms and the electoral costs of these rules to policy-makers.