The New Word Hunter project sought to engage families of Year 1 children with the aim of extending their vocabularies beyond everyday language. Early vocabulary development has been linked to later performance in reading comprehension, as well as to socio-economic status. This project sought to recruit families from two diverse school communities as partners in encouraging their children to increase their lexical repertoires by providing them with vocabulary rich books, supplementary resources and advice. Utilising a pre-and post-test design with a treatment group and comparison group in each of two contrastive schools, the study investigated both receptive and expressive vocabulary performance, with a focus on words in the Tier-2 category, drawing on the work of Beck and McKeown. Initial assessment found unanticipated similarities in the performance of children from low and middle SES backgrounds, but differences related to language background and gender. Based on this assessment, we suggest that educators may be underestimating young children’s receptive and expressive language competence. Findings of the comparative analysis of pre- and post-test results indicate that the intervention was effective in improving children’s understanding of challenging words included in fictional and nonfiction texts provided in resource packs. However, this was only the case in one school, Pleasant Rise, which had a socially and culturally diverse community with a moderate level of disadvantage; it was not the case in Pelican Point, a school serving a highly disadvantaged community. In discussing the findings, we suggest there may be an interaction between teacher attitudes, family interventions and child outcomes, even when educators’ pedagogy is not the focus of the interventions. Acknowledging limitations of the project, we propose that directly encouraging parents and carers to engage in vocabulary extension with their children, and providing high quality and engaging materials, is worth further attention.