Objective Previous studies demonstrate that campaigns play an important role in mobilizing citizen participation in elections. The present analysis examines the effects of campaign spending on voter turnout in the state legislative setting where our knowledge of campaign effects is quite limited. Method In an examination of state legislative elections across 20 states over two election cycles, the analysis considers the influence of candidate spending on voter turnout. Results The findings demonstrate that campaign spending has a strong influence on voter participation; however, this effect is mitigated by contextual features. Legislative professionalism reduces the influence of spending, while the presence of a high‐stimulus statewide election enhances it. In addition, challenger spending is more effective at stimulating participation than incumbent spending. Conclusions Higher levels of campaign spending increase voter participation in state legislative elections; however, these effects vary according to context. These findings have important implications for theories of participation in American democracy as well for normative issues concerning the role of money in elections.