Background: A wealth of evidence supports the important role high-quality parent-child interactions play in children's early language acquisition. However, the impact on later language outcomes remains unclear. Aims: To examine the associations between responsive parental behaviours across the early years and child language outcomes at age 7 years with families from an Australian longitudinal cohort study (N = 1148, 50% female). Methods & Procedures: At child ages 12, 24 and 36 months, parents completed a self-report measure of responsive parental behaviours. Child language was directly assessed at age 7 using the Clinical Evaluation of Language Fundamentals, 4th edition (CELF-4), Australian Standardisation. Linear regression was used to examine associations between responsive parental behaviours from 12 to 36 months (consistently high, inconsistent and consistently low responsive parental behaviours at the three time points) and language scores at age 7 years. Adjusted models were run, including the following potential confounders: child sex; birth weight; birth order; maternal education; socio-economic disadvantage; non-English-speaking background; family history of speech--language problems; mother's vocabulary score; maternal mental health score; and mother's age at birth of child. A final adjusted model was run, including the potential confounder variables as well as adjusting for children's earlier language skills. Outcomes & Results: Linear regression results showed children with parents who rated high on responsive parental behaviours at all three time points had higher mean language scores at age 7 than children whose parents reported low responsive parental behaviours across early childhood. This association attenuated after adjusting for earlier child language skills. Conclusions & Implications: Findings support the consistent use of responsive parental behaviours across the very early years of childhood to support long-term language outcomes. Findings also suggest that models of surveillance and support which monitor and assist families at multiple time-points over the early years are likely to be most effective for preventing ongoing language difficulties.