This paper describes the cultural and linguistic diversity of Australian preschool children and their parents in order to guide resourcing, assessment, and intervention practices. Data were analysed from a nationally representative sample of 4,983 Australian preschool children. Over one fifth (21.9%) of the children were regularly spoken to in a language other than English. The majority (86.0%) spoke English as their first language; and 12.2% of the children spoke one of 35 other languages. After English, the most common first languages were: Arabic (1.6%), Cantonese (1.3%), Vietnamese (1.0%), Greek (0.8%), and Mandarin (0.8%). Italian was the most common additional language, spoken by 2.9% of the children. Commonly spoken children’s languages differed by state/territory and showed different trends compared with Australian census data (ABS, 2006). Most of the children’s parents spoke English as the primary language at home; however, 42 other primary languages were also spoken. Significant resourcing of the Australian speech pathology, early years education, and interpreting sectors is required to accommodate the diverse cultural and linguistic heritage of children. Resourcing should be based on data about Australia’s children, rather than the publicly available Australian census data.