<p>Previous studies have suggested that individuals with tetralogy of Fallot (TOF) may exhibit neurodevelopmental abnormalities in the prefrontal cortex (PFC), potentially originating during the fetal period, although conclusive evidence remains limited. This study analyzed cell types and developmental states in the fetal PFC of TOF and healthy fetuses using single-nucleus RNA sequencing (snRNA-seq). Compared with gestational age-matched healthy controls, the TOF fetus exhibited marked delays in brain development and widespread transcriptional dysregulation, with developmental delay estimated to be up to or exceeding one month. Further analysis identified key genes potentially involved in the dysregulation of excitatory neuron development, including <i>FLRT2</i>, <i>MEIS2</i>, and <i>SOX11</i>, all of which play essential roles in neuronal development. A TOF-associated SGCZ^high subtype was identified in inhibitory neurons, with dysregulation of key regulatory genes and associated transcriptional networks, such as NFATC2-NELL1. In non-neuronal cell types, glial progenitor cells in the TOF fetus were more likely to differentiate into a neuroprotective NRG1^high subtype rather than oligodendrocytes, suggesting impaired myelination and a potential compensatory role of the NRG1^high subtype in TOF-associated neurodevelopmental abnormalities. Cell-cell communication analysis further elucidated the molecular pathways underlying TOF-associated neurodevelopmental defects. Our findings provide preliminary evidence for developmental delays in the PFC of TOF and identify potential regulatory genes involved, thereby providing a molecular and cellular basis for understanding TOF-associated brain developmental disorders.</p><p><i>Trial registration</i>: The trial registration number: ChiCTR2300070041; date of registration: 2023.03.31.</p>