Public officials can be reluctant to use citizens’ input in decision‐making, especially when turnout is low and participants are unrepresentative of the wider population. Using Fritz Scharpf's democratic legitimacy approach, the authors conducted a survey‐based vignette experiment to examine how the input legitimacy of participatory processes affects (1) public officials’ willingness to use public participation in administrative decision‐making, (2) their assessment of the quality of the policy decision, and (3) their anticipation of popular support for the policy outcome. The study shows that turnout and participants’ representativeness have a positive and significant effect on public officials’ attitudes toward public participation. Specifically, participants’ representativeness influences public officials’ willingness to use citizens’ inputs more than turnout.