Recent studies have shown that females are often at a greater risk of injury than males in frontal crashes. National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) 2000–2015 data analysed in this study showed that 44% of the females involved in frontal crashes were between 25th and 75th height percentile. This study aims to analyse injury risk for mid-sized females in frontal crashes and evaluate how variability within mid-sized females affects the injury risk, and potential countermeasures. Two mid-sized female morphologies of the simplified Global Human Body Models Consortium (GHBMC) model were utilized:​ a) a simplified 50th percentile adult female GHBMC FE human model (F50);​ and b) a scaled 50th percentile adult female model (F50-S) obtained by uniformly scaling the simplified GHBMC 5th percentile female model based on seated height. Paired frontal impact simulations were run and the resulting body region injury risks were compared between the models. Statistically significant differences were observed for the head, thorax and lower extremity body regions. Interpretation of machine learning models developed for chest deflection showed the same top four most significant parameters (crash and restraint), but their impact was different for the two models, thus influencing the potential countermeasures for mitigating thoracic injuries.