Despite the importance of abdominal injuries in children involved in motor vehicle collisions, only two papers have reported experimental data quantifying the pediatric abdominal response to belt loading. One developed and characterized a porcine model of the pediatric abdomen and the other presented a series of tests performed on a single pediatric (7-year-old female) post-mortem human subject (PMHS) and used the data to evaluate the efficacy of the porcine model. The current paper presents the results from an additional pediatric (6-year-old female) PMHS test series and an expanded evaluation of the porcine model using the combined PMHS data. The two PMHS exhibited remarkably similar abdominal stiffness, both by level (upper and lower) and by rate (quasi-static and ∼2 m/s dynamic). Both PMHS and swine exhibited the same stiffness trend by abdominal level (lower stiffer than upper: 3444 N reaction force at 30.5 mm of displacement compared to 1756 N in the 6-year-old dynamic tests). The magnitude of lower abdomen stiffness was slightly less in the swine than in the PMHS (the average dynamic PMHS response was 1086 N greater than the porcine envelopes at 30.5 mm displacement) while the upper abdomen PMHS responses fit within the porcine response envelope.