ImportanceThe Ages and Stages Questionnaire (ASQ) is a commonly used developmental screening tool, but its utility is debated.ObjectivesTo conduct a a systematic review and meta-analysis to evaluate ASQ’s utility as a screening or diagnostic tool to identify developmental delay in children aged 12-60 months.Data SourcesMedline, EMBASE, CINAHL, PsycINFO, and Mednar were searched from inception until December 2021.Study SelectionStudies meeting both criteria were included. ASQ was performed at age 12 to 60 months or where the median age at ASQ was at least 12 months and formal developmental assessments were done within 2 months of ASQ.Data Extraction and SynthesisTrue positive, false positive, false negative, and true negatives from individual studies were extracted. Meta-analysis was conducted with Stata version 16.1. Risk of bias was assessed using the QUADAS-2 tool. Certainty of evidence (COE) was assessed using GRADE guidelines.Main Outcomes and MeasuresAbility of ASQ scores more than 2 SDs below the mean in more than 1 domain (ASQ-2SD) to identify any developmental delay or severe delay. Based on generally accepted interpretation of likelihood ratio (LR) values, a positive LR (PLR) more than 5 and a negative LR (NLR) of 0.2 or less were considered necessary to rule in or rule out developmental delay, respectively, with at least moderate probability.ResultsInitial search yielded 5777 citations of which 43 were included in the review. Of them, 36 were included in the meta-analysis. The pooled sensitivity, specificity, PLR, and NLR are as follows: ASQ-2SD to predict any delay in 1 or more domain (n = 16), 0.77 (95% CI, 0.64-0.86), 0.81 (95% CI, 0.75-0.86), 4.10 (95% CI, 3.17-5.30), and 0.28 (95% CI, 0.18-0.44); ASQ-2SD to predict severe delay in 1 or more domain (n = 15), 0.84 (95% CI, 0.75-0.90), 0.77 (95% CI, 0.71-0.82), 3.72 (95% CI, 2.98-4.64), and 0.20 (95% CI, 0.13-0.32); ASQ-2SD motor domain to predict motor delay (n = 7), 0.41 (95% CI, 0.26-0.57), 0.94 (95% CI, 0.87-0.97), 6.5 (95% CI, 3.8-11.1), and 0.63 (95% CI, 0.50-0.81); and ASQ-2SD cognitive domain to predict cognitive delay (n = 2), 0.44 (95% CI, 0.24-0.65), 0.93 (95% CI, 0.81-0.95), 6.4 (95% CI, 2.4-16.8), and 0.61 (95% CI, 0.43-0.86). The COE was low/very low.Conclusions and RelevanceIf a child aged 12 to 60 months passes all ASQ domains, there is a moderate probability that they do not have severe developmental delay (low COE). If a child aged 12-60 months fails the motor or cognitive domain of ASQ, there is a moderate probability that they have some motor or cognitive delay, respectively (very low COE).Trial RegistrationPROSPERO (CRD42021268543).