Firm training is key to meeting changing skill demands, yet little is known about the role of workers’ beliefs in shaping training participation. In a survey of 3,701 workers in Germany, we document that they expect substantial returns to firm training – both in terms of earnings and non-pecuniary outcomes such as promotion chances, job task complexity, or enjoyment. These beliefs predict actual and intended training participation. Lower-skilled workers anticipate smaller non-pecuniary returns, partly explaining their lower uptake. An information treatment addressing return beliefs significantly increases training intentions among lower-skilled workers, suggesting that targeting beliefs may help narrow participation gaps between lower- and higher-skilled workers.