To predict others’ behavior and make their own choices, voters and candidates can rely on information provided by polls and past election results. We isolate the impact of candidates’ rankings using an RDD in French local and parliamentary two-round elections, where up to 3 or 4 candidates can qualify for the second round. Candidates who barely ranked first in the first round are more likely to run in the second round (5.6pp), win (5.8pp), and win conditionally on running (2.9 to 5.9pp), than those who barely ranked second. The effects are even larger for ranking second instead of third (23.5, 9.9, and 6.9 to 12.2pp), and ranking third instead of fourth also increases candidates’ second round outcomes (14.6, 2.2, and 3.0 to 5.0pp). These results are largest when the candidates have the same political orientation (making coordination relatively more important and desirable), but they remain strong when two candidates only qualify for the second round (and there is no need for coordination), suggesting that bandwagon effect is an important driver of voter behavior and election outcomes.