Inbreeding-environment interactions occur when inbreeding leads to differential fitness loss in different environments. Inbred individuals are often more sensitive to environmental stress than are outbred individuals, presumably because stress increases the expression of deleterious recessive alleles or cellular safeguards against stress are pushed beyond the organism's physiological limits. We examined inbreeding-environment interactions, along two environmental axes (temperature and rearing host) that differ in the amount of developmental stress they impose, in the seed-feeding beetle Callosobruchus maculatus. We found that inbreeding depression (inbreeding load, L) increased with the stressfulness of the environment, with the magnitude of stress explaining as much as 66% of the variation in inbreeding depression. This relationship between L and developmental stress was not explainable by an increase in phenotypic variation in more stressful environments. To examine the generality of this experimental result, we conducted a meta-analysis of the available data from published studies looking at stress and inbreeding depression. The meta-analysis confirmed that the effect of the environment on inbreeding depression scales linearly with the magnitude of stress; a population suffers one additional lethal equivalent, on average, for each 33% reduction in fitness induced by the stressful environment. FoxandReed-Larvalsurvival.xlsSurvival data for larvae from two populations (SI=South India and BF=Burkina Faso) of Callosobruchus maculatus reared at three temperature (l=17C, m=27C, h=37C) on two hosts (c=cowpea, m=mung bean). Data are presented as the stage at which larvae died (egg did not develop, egg developed but did not hatch, egg hatched but did not produce an adult, or an adult emerged) for each family. The first sheet presents data for each family. Families are grouped into blocks, with each block containing two inbred and two outbred families, as described in the paper. The additional sheets present summaries of the data, by blocks, or population/treatments. d = inbreeding depression, L = inbreeding load.