Inbreeding depression occurs when individuals who are closely related mate and produce offspring with reduced fitness. Although inbreeding depression is a genetic phenomenon, the magnitude of inbreeding depression can be influenced by environmental conditions and parental effects. In this study, we tested whether size-based parental effects influence the magnitude of inbreeding depression in an insect with elaborate and obligate parental care (the burying beetle, Nicrophorus orbicollis). We first tested for size-dependent maternal effects on offspring size using a phenotypic manipulation experiment where we created large and small adults by manipulating the amount of time they fed as larvae. Consistent with studies of other Nicrophorus species, we found that larger mothers produced larger offspring. We next tested for size-dependent parental effects on the magnitude of inbreeding depression in two traits: mean larval mass and survival from larval dispersal to eclosion. As in our first experiment, we found that larger parents produced larger offspring. However, larval mass was also influenced by the interaction between parental body size and inbreeding status: when parents were small, inbred larvae were smaller than outbred larvae, but when parents were large this pattern was reversed. In contrast, survival from larval dispersal to adult emergence showed inbreeding depression that was unaffected by parental body size. Our results suggest that size-based parental effects can generate variation in the magnitude of inbreeding depression. However, further work is needed to dissect the mechanisms through which this might occur and to better understand why parental size influences inbreeding depression in some traits but not others.