The lack of inclusive educational interventions for children with behavioural disorders exacerbates the already concerning problem of school failure in Peru. There is a scarcity of educational proposals that intertwine psychology and engineering, leaving the study of the impacts of postural ergonomics on selective attention unattended despite the frequent mismatch between the furniture and the student’s anthropometric measurements. Consequently, this interdisciplinary research, through a case study of Peruvian primary school children disaggregated into ADHD (neurodivergent) and non-ADHD (neurotypical) samples, evaluates the impact of postural ergonomics on selective attention and further assesses the difference between the magnitude of such impact on the neurodivergent and neurotypical samples. The impact assessment is based on the correlation between the d2R test for selective attention results and the evaluation of postural ergonomic correctness. Results from the paired T-test coupled with a Cohen’s-D of over 1.95 demonstrate that correct ergonomic posture leads to a significant improvement in selective attention and that such improvement is +1.5 points higher for neurotypicals than for neurodivergents. Ultimately, to provide a tangible improvement to education, and after defining the incoherence between current school furniture and the sample’s anthropometric measurements, recommended measurements for adjustable furniture for Peruvian schools that ensure correct postural ergonomics are proposed.