This study examines changes in parent support and child emergent literacy skills over time as children moved from Head Start into kindergarten. It compares the transactional parent-child influences in families randomly assigned in Head Start to receive an enriched home visiting program that emphasized parents as teachers relative to a control group. In addition, it examined the impact of pre-intervention levels of parental support on change over time in child emergent literacy skill acquisition. It thus tested the logic model of the intervention--REDI-P (Research-based Developmentally-Informed-Parent)--and assessed moderation of intervention impact. Children and their parents were recruited from 26 Head Start Programs in three counties of Pennsylvania for a randomized-trial evaluation of a home visiting intervention designed to increase parental involvement in interactive reading and learning games. The Head Start programs served a range of small urban, suburban, and rural communities. Participants included two cohorts of children recruited in sequential years (total N = 210; mean age at time 1 = 4.8; 55% girls; 20% Hispanic; 25% African-American; and 55% European American). The caregivers who participated in this study (hereafter referred to as "parents") were 88.57% mothers, 4.27% fathers, 5.24% grandmothers, and 1.92% other (e.g. other relative, stepparent, or foster parent). Data was collected from home visits, structured interviews, recorded parent-child interaction sessions, and pre- and post-test assessments conducted by research assistants. Findings suggest that the REDI-P program improved supportive parenting skills for the sub-group of parents with initially poorer skills in this area. These changes emerged primarily in the context of parent-child reading and teaching activities, which were the direct focus of the intervention and did not appear to generalize more broadly. Additionally, parents who entered the program with more supportive parenting skills were able to take the most advantage of the teaching games and activities provided by the program, and their children showed the greatest gains in literacy skills. Tables and figures are appended.