Preschool children considered at risk for future reading difficulties experience unique and complex combinations of risk factors. In this exploratory study, we used latent profile analysis (LPA) to investigate the underlying classifications of children identified as at-risk for reading difficulties (N = 281) along selected cognitive, psychological, ecological, and child-related characteristics. We then used latent profile moderation, a methodology that extends the extensive prior literature on LPA, to explore for whom a supplemental, small-group emergent literacy intervention yielded effects. Latent profile moderation allowed us to explore whether specific subgroups of children characterized by multiple risk factors made significantly greater gains from the intervention than others. We identified four distinct profiles of preschool children considered at risk for reading difficulties, and the four profiles varied across cognitive, psychological, and ecological factors as well as on emergent literacy outcomes at the end of preschool. Further, we found a significant, moderate effect of the intervention on children's letter writing in Profile 1. Thus, latent profile moderation analysis may help clarify the dynamic interplay of multiple salient factors relative to intervention outcomes and identify for whom interventions are effective. [This paper will be published in the "Journal of Education for Students Placed at Risk (JESPAR)."]