Ambient heat exposure during pregnancy is associated with adverse outcomes, with emerging evidence suggesting potential impacts on neurodevelopment. This scoping review synthesises human and animal evidence on the association between prenatal ambient heat exposure and adverse neurodevelopmental outcomes. A search was conducted across MEDLINE, Global Health, Web of Science, PsycINFO, and CINAHL. Studies published up to May 2025 examining prenatal ambient heat exposure and neurodevelopmental outcomes, including congenital malformations and mental health conditions, were included. Two reviewers independently screened and extracted in duplicate using Covidence. Studies were categorised based on short-term (congenital anomalies, early brain metrics) or long-term outcomes (childhood behaviour and psychiatric diagnoses). The search yielded 8,189 studies, with 60 meeting the inclusion criteria (18 human, 42 animal). Most animal experimental studies (n = 32) used rodents and imposed extreme, hyperthermia-inducing temperatures. Epidemiological human studies were heterogeneous in terms of exposures and methodological approaches. For short-term outcomes, such as malformations and brain parameters, animal studies reported adverse effects of prenatal heat on neurodevelopment, whereas human findings were conflicting. Minimal human and animal studies focused on long-term outcomes, such as mental health, but those that did generally reported adverse outcomes. Overall, the evidence suggests a potential link between prenatal heat exposure, CNS malformations and altered brain size in animal models; however, the implications for humans remain uncertain. Animal studies often employed unrealistic heat exposures, limiting their applicability to humans. In contrast, human studies are limited in number and yield inconsistent findings. This review identifies three key priorities to strengthen the evidence: (1) designing animal experiments with realistic heat exposures to improve translational evidence, (2) prioritising large-animal models over rodents to better approximate human physiology and (3) standardising outcome and exposure metrics in human studies to improve comparability and reproducibility.