A long tradition within political science examines the impact of party canvassing on voter participation. Very little of this work, however, is comparative in scope. This essay examines how system-level characteristics shape the nature and impact of party canvassing and how voters respond to those efforts. Parties are found to target the same types of potential voters everywhere – those who are likely to participate. However, one important difference is that overall levels of party contact are far greater in candidate-based systems than in proportional representation (PR) systems. Party mobilization, therefore, cannot explain the higher rates of turnout observed in PR systems.