Qualitative job insecurity may be associated with less (hindrance effect) and more (challenge effect) organizational citizenship behaviour (OCB). This article disentangles both effects by introducing an intermediate variable. The authors test whether basic need satisfaction explains the hindrance effect (i.e. less intrinsically motivated OCB); and whether there is a remaining, direct positive path to OCB reflecting the challenge effect (i.e. more instrumentally motivated OCB). In addition, they investigate whether these relationships vary with age. Multi–group path analysis on a Belgian sample (N = 3243) of young (18 30 years), prime age (31 49 years) and mature age workers (50 +) reveals that qualitative job insecurity frustrates basic needs across all age groups, but most strongly among mature age workers (i.e. hindrance effect). The authors find a remaining positive path (i.e. challenge effect) that is equally strong across all age groups. In sum, qualitative job insecurity is more hindering than challenging, in particular for older workers.