Voting models assume that voting costs impact turnout. As turnout declined across advanced democracies, governments enacted reforms designed to reduce costs in order to increase participation. Internet voting, used in elections across a dozen countries, promises to reduce voting costs dramatically. Yet identifying its effect on turnout has proven difficult. In this article, we use original panel data of local elections in Ontario, Canada and fixed effects estimators to estimate internet voting's effect. The results show internet voting can increase turnout by 3.5 percentage points, with larger increases when vote by mail (VBM) is not yet adopted, and greater use when registration is not required. Our estimates suggest that internet voting is unlikely to solve the low turnout crisis, and imply that cost arguments do not fully account for recent turnout declines.Voter turnout is one of the most widely examined areas of political science. Interest in understanding turnout has only grown as electoral participation has declined in advanced democracies over the past several decades.1 Low electoral participation calls democracy into question, and undermines government legitimacy, political representation and equitable public policies.2 To raise participation levels, politicians and administrators often consider electoral reforms, such as compulsory voting or universal voter registration. Differences in electoral rules have been shown to account for variations in turnout across advanced democracies, 3 and some electoral reforms can even affect public policy by changing who participates. 4 But perhaps the simplest and most common electoral reforms aim to reduce voting costs by increasing convenience. Convenience voting options include early voting, extended polling hours and postal voting. 5 These reforms respond to the theory -proposed in basic, rational choice models of voter turnout -that turnout is a function of voting's relative costs and benefits.