Background Caesarean section (CS) rates are rising globally. Long‐term adverse outcomes after CS might be reduced when the optimal uterine closure technique becomes evident. Objective To determine the effect of uterine closure techniques after CS on maternal and ultrasound outcomes. Search strategy Literature search in electronic databases. Selection criteria Randomised controlled trials (RCTs) or prospective cohort studies that evaluated uterine closure techniques and reported on ultrasound findings, perioperative or long‐term outcomes. Data collection and analysis Twenty studies (15 053 women) were included in our meta‐analyses for various outcomes. We calculated pooled risk ratios (RR) and weighted mean differences (WMD) with 95% CI through random‐effect analysis. Main results Residual myometrium thickness (RMT), reported in eight studies (508 women), decreased by 1.26 mm after single‐ compared with double‐layer closure (95% CI −1.93 to −0.58), particularly when locked sutures were used. Healing ratio RMT/adjacent myometrium thickness (AMT) decreased after single‐layer closure (WMD −7.74%, 95% CI −13.31 to −2.17), particularly in the case of locked sutures. Niche prevalence increased (RR 1.71, 95% CI 1.11–2.62) when the decidua was excluded. Dysmenorrhea occurred more often in the single‐layer group (RR 1.23, 95% CI 1.01–1.48), whereas incidence of uterine rupture was similar (RR 1.91, 95% CI 0.63–5.74). Conclusion Double‐layer unlocked sutures are preferable to single‐layer locked sutures regarding RMT, healing ratio and dysmenorrhoea. Excluding the decidua seems to result in higher niche prevalence. As thin residual myometrium or niches may serve as intermediates for gynaecological and reproductive outcomes, future studies should focus on these outcomes. Tweetable #Uterineclosuretechniques after #caesarean affect #longtermoutcomes. Tweetable #Uterineclosuretechniques after #caesarean affect #longtermoutcomes.