Background Preschool screening for developmental difficulties is increasingly becoming part of routine health service provision and yet the scope and validity of tools used within these screening assessments is variable. The aim of this review is to report on the predictive validity of preschool screening tools for language and behaviour difficulties used in a community setting. Methods Studies reporting the predictive validity of language or behaviour screening tools in the preschool years were identified through literature searches of Ovid Medline, Embase, EBSCO CINAHL, PsycInfo and ERIC. We selected peer-reviewed journal articles reporting the use of a screening tool for language or behaviour in a population-based sample of children aged 2–6 years of age, including a validated comparison diagnostic assessment and follow-up assessment for calculation of predictive validity. Results A total of eleven eligible studies was identified. Six studies reported language screening tools, two reported behaviour screening tools and three reported combined language & behaviour screening tools. The Language Development Survey (LDS) administered at age 2 years achieved the best predictive validity performance of the language screening tools (sens 67%, spec 94%, NPV 88% and PPV 80%). The Strengths and Difficulties Questionnaire (SDQ) administered at age 4 years achieved the best predictive validity compared to other behaviour screening tools (Sens 31%, spec 93%, NPV 84% and PPV 52%). The SDQ and Sure Start Language Measure (SSLM) administered at 2.5 years achieved the best predictive validity of the combined language & behaviour assessments (sens 87%, spec 64%, NPV 97% and PPV 31). Predictive validity data and diagnostic odds ratios identified language screening tools as more effective and achieving higher sensitivity and positive predictive value than either behaviour or combined screening tools. Screening tools with combined behaviour and language assessments were more specific and achieved higher negative predictive value than individual language or behaviour screening tools. Parent-report screening tools for language achieved higher sensitivity, specificity and negative predictive value than direct child assessment. Conclusions Universal screening tools for language and behaviour concerns in preschool aged children used in a community setting can demonstrate excellent predictive validity, particularly when they utilise a parent-report assessment. Incorporating these tools into routine child health surveillance could improve the rate of early identification of language and behavioural difficulties, enabling more informed referrals to specialist services and facilitating access to early intervention.