Does electoral competitiveness boost turnout in U.S. House elections? Using an individual panel of turnout records compiled from the voter files of all 50 states, we exploit variation in district competitiveness induced by the 2012 redistricting cycle to provide credible estimates of the effect of competitiveness on turnout. When tracking the same voters across time under differing levels of competitiveness, we precisely estimate the effect on turnout to be near zero. Although past cross-sectional research reports a link between competitiveness and turnout in House elections, we demonstrate that residents in competitive districts differ markedly from those in uncompetitive districts along a number of observable characteristics correlated with turnout, and we argue that this induces bias in most cross-sectional estimates. Secondary evidence tracking voter perceptions of competitiveness and campaign behavior provides support for our finding. Voters have scant awareness of competitiveness in House elections, and, while campaign spending is strongly related to competitiveness, it is directed into avenues that do not appreciably increase turnout. Our findings have important implications for the competitiveness--turnout relationship in other electoral settings with geographically compact, single-member districts.