CONTEXT: Evidence is emerging that preterm infants are at risk for autism spectrum disorder (ASD). OBJECTIVES: To conduct a systematic review and meta-Analysis to estimate the prevalence of ASD in preterm infants. DATA SOURCES: Medline (via PubMed and Ovid), Embase, PsycINFO, and relevant conference proceedings were searched in May 2017. STUDY SELECTION: Original studies in which researchers report on the prevalence of ASD using diagnostic tests in children born preterm were included. Studies in which researchers used only ASD screening tools were excluded. DATA EXTRACTION: Relevant data were extracted independently by 3 authors. RESULTS: Researchers in a total of 18 studies (3366 preterm infants) used ASD diagnostic tools. The median gestation, birth weight, and age at assessment were 28.0 weeks (range: 25.1-31.3 weeks), 1055 g (range: 719-1565 g), and 5.7 years (range: 1.5-21 years), respectively. Meta-Analysis revealed that the overall prevalence rate for ASD was 7% (95% confidence interval: 4% to 9%). The funnel plot and Egger's test revealed that there was probably no evidence of publication bias. LIMITATIONS: The limitations were significant heterogeneity and a lack of studies from middleand low-income countries. CONCLUSIONS: The prevalence of ASD is significantly high in the preterm population. Adequate resources are needed to improve the outcomes of these children.