Despite being previously banned due to long-term health effects, Per- and polyfluoroalkyl substances (PFAS) remain widespread in the environment, accumulating in animals and humans. This systematic review and metaanalysis explores associations between exposure to PFAS and asthma onset, wheezing, atopic dermatitis, and eczema in children and adolescents while addressing exposure timing and sex-specific differences. After comprehensive search conducted in several databases, including risk of bias, study heterogeneity, and quality of evidence evaluation, the review included 28 observational studies, most with low risk of bias in all domains. PFAS exposure was not significantly associated with asthma onset (OR:1.03, CI:0.99;1.07), but revealed significantly lower association in the prenatal period (OR:0.97, CI:0.94;0.99), higher in the postnatal period (OR:1.20, CI:1.07;1.35), and no differences among sexes. PFAS exposure (mainly prenatal) was associated with 4 % significantly lower odds of wheezing (OR:0.96, CI:0.94;0.98), higher in girls (OR:0.94, CI:0.91;0.98) than in boys (OR:0.97, CI:0.94;1.00). No significant impact was noted on atopic dermatitis (OR:1.04, CI:0.94;1.16), while