This study investigated whether participating in inter‐organisational (i.e. self‐directed, non‐strategic) employee volunteering, which is common but rarely studied, is associated with increased organisational commitment. We find evidence for this relation in a sample (N = 385) of employee volunteers and their non‐volunteering co‐workers. We statistically account for self‐selection into the volunteering program by incorporating individual motives for volunteering. Volunteers compared to non‐volunteers exhibited relatively stronger motives of expressing altruistic values and avoiding negative affect, but a weaker motive of attaining career advancement. Our findings point to an efficient way of increasing organisational commitment that is relatively inexpensive to implement. They also complement existing research from other employee volunteering contexts, pointing to a possible trade‐off between the desired outcomes of effectively managing volunteering programs.