AbstractOocyte maturation arrest is one of the important causes of female infertility, but the genetic factors remain largely unknown.PABPC1L, a predominant poly(A)‐binding protein inXenopus, mouse, and human oocytes and early embryos prior to zygotic genome activation, plays a key role in translational activation of maternal mRNAs. Here, we identified compound heterozygous and homozygous variants inPABPC1Lthat are responsible for female infertility mainly characterized by oocyte maturation arrest in five individuals.In vitrostudies demonstrated that these variants resulted in truncated proteins, reduced protein abundance, altered cytoplasmic localization, and reduced mRNA translational activation by affecting the binding of PABPC1L to mRNA.In vivo, three strains ofPabpc1lknock‐in (KI) female mice were infertile. RNA‐sequencing analysis showed abnormal activation of the Mos‐MAPK pathway in the zygotes of KI mice. Finally, we activated this pathway in mouse zygotes by injecting humanMOSmRNA, and this mimicked the phenotype of KI mice. Our findings reveal the important roles of PABPC1L in human oocyte maturation and add a genetic potential candidate gene to be screened for causes of infertility.