A child's exposure to arsenic (As) can begin in utero through placental transfer to the fetus. There is a growing body of epidemiologic evidence suggesting an association between As exposure and neuropsychological development. Therefore, our objective was to describe the consequences of maternal and/or childhood As exposure on children's neuropsychological development. We conducted a scoping review with a systematic search of the PubMed, Scopus, EMBASE, Web of Science, and PsycINFO databases. We included studies that assessed the association between maternal and/or childhood As exposure and neuropsychological development in children up to an average of 12 years of age. A total of 77 studies were included, most of which were published between 2020 and 2024 (44.1%), conducted in the United States of America (18.2%) and Bangladesh (16.9%), and involved participants with a median age of 6.6 years. Most studies performed cross-sectional analyses (51.9%) and assessed exposure to elements other than As (64.9%). Childhood was the most frequently studied exposure window (57.2%), and urine was the most commonly used biomarker of exposure (58.4%), followed by blood or serum (32.3%). Cognition was the most frequently evaluated neuropsychological domain (94.8%), followed by psychomotor function (40.3%) and social-emotional function (29.9%). Most studies reported evidence of a negative impact of As exposure on children's neuropsychological development (73.7%), while some found no changes (27.3%) and a few suggested an improvement (1.3%). An important limitation is that most studies measured total urinary As without speciation into inorganic versus organic forms, which limits the validity of dose-response conclusions based on total arsenic concentrations. This review highlights the potential deleterious neuropsychological effects of maternal and/or childhood As exposure while also identifying areas where the evidence remains inconclusive.