An alarming number of American pre-school children lack sufficient language and literacy skills to succeed in kindergarten. The type of curriculum that is available within pre-kindergarten settings can impact children's academic readiness. This work presents results from an evaluation of two language and literacy curricula (i.e., Let's Begin with the Letter People and Doors to Discovery) from a random assignment study that occurred within three settings (i.e., Head Start, Title 1, and universal pre-kindergarten) and included a control group. The design included a mentoring and non-mentoring condition that was balanced across sites in either curriculum condition. A pre and post-test design was utilized in the analyses, with children (n = 603) tested before the intervention and at the end of the year. Multilevel growth curve modeling, where the child outcomes (dependent measures) are modeled as a function of the child's level of performance and rate of growth between pre and post-testing, was used for all analyses. Results indicated that in many key language/literacy areas, the skills of children in classrooms using either one of the target curricula grew at greater rates than children in control classrooms. This was especially true in the Head Start programs. The findings from this study indicate that at-risk children can benefit from a well-specified curriculum. Additionally, findings demonstrate that a well-detailed curriculum appeared to be less important for children from higher income families. The impact of mentoring was less clear and seemed dependent on the type of skill being measured and type of program. Pre- and post-test means, standard deviations, and sample sizes for standardized child outcome variables are appended. (Contains 2 tables and 4 figures).