Do participants in funded occupational pension plans (OPPs) perceive them as legitimate? This study addresses that question by considering both input legitimacy – participants’ satisfaction with OPPs’ decision-making processes – and output legitimacy – participants’ satisfaction with the benefits and financial returns of OPPs. It draws on an original survey conducted in Austria, Denmark, Germany, Ireland, the Netherlands, and Spain in 2023. The analysis indicates moderate satisfaction with input and output legitimacy across all six countries. Moreover, behavioural factors – having gathered information about their OPP or engaged in OPP decision-making processes – are strong predictors of input and output legitimacy.