Oral language skills underpin children's educational success and enhance positive life outcomes. Yet, significant numbers of children struggle to develop competence in speaking and listening, especially those from areas of high economic deprivation. A tiered intervention model, graduating the level of provision in line with levels of need, has been posited as most appropriate for supporting children's language development. The first tier, or universal provision, is characterised by high-quality, evidence-informed language teaching for all. To date, our understanding of effective universal language delivery remains limited, particularly in the primary-school age range. This systematic review addresses this gap by identifying and evaluating existing evidence with the aim of informing practice and future research. Following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a systematic search protocol was used to identify experimental and quasi-experimental studies evaluating universal approaches designed to support children's oracy skills. Thirty-one studies were identified for inclusion and their characteristics and findings are reported and their reliability evaluated. Studies provide indicative evidence for the effectiveness of interactive book reading, structured vocabulary programmes, manualised curricula and approaches involving speech and language therapists. The strengths and weaknesses of our current knowledge are outlined and implications for practice and research are discussed.