Despite calls for research on how the socio-economic environment may be related to temperament, we still do not know enough about the relationship between temperament and socio-economic disadvantage (SED). A particularly under-researched question in temperament research is how SED may moderate the temperament-parenting and the temperament-child psychopathology links. The article argues that, to develop theory, future temperament studies should seek to explore how the timing, specificity or accumulation, level and duration, and change of SED may be related not only to temperament but also to links between temperament and parenting and between temperament and child psychopathology.