Self-injurious behaviors (SIB) are problematic for many children with autism spectrum disorders (ASD). Existing models to explain factors contributing to SIB fail to account for a large proportion of variance in SIB. This study attempted to explain a greater proportion of variance in SIB by addressing methodological/theoretical limitations in previous research using a sample of 2341 youth with ASD. The model comprised of predictors identified by the prior study continued to explain only a small proportion of variance in the SIB score (R[superscript 2] = 0.13). Revisions to the model failed to substantially improve model fit. Results suggest that psychological, cognitive, and behavioral factors alone do not adequately explain common measures of SIB and highlight the need for further research.