What can interest group scholars, practitioners, and policymakers conceptually learn about influence from formal theories of informational lobbying? This article has two objectives. The first is to help clarify the fundamental components of informational lobbying models and how they differ from other lobbying mechanisms. To illustrate informational lobbying and influence attempts, I provide examples from a sample of 91 emails sent by interest groups to the permanent Dutch representative in the European Union. The second objective is to list common determinants of interest groups' influence in informational lobbying models and illustrate when and why they are especially salient. This paper summarizes how the nature of communication and preferences shape interest group influence.