In this article I analyze a model of interest group influence on legislative voting through information transmission. The model shows how interest groups may manipulate voting coalitions to their advantage by crafting different messages to target different winning coalitions. Furthermore, if access to legislators is costly, the interest groups prefer to coordinate with allied legislators by providing them with information that helps them to persuade less sympathetic legislators. The model reconciles informational theories of lobbying with empirical evidence suggesting that interest groups predominantly lobby those who already agree with them. The model also makes new predictions about the welfare effects of interest group influence: from an ex ante perspective, informational lobbying negatively effects the welfare of legislators. The results highlight the need for more theories of persuasion that take collective choice institutions into account.