Rollover crashes involving side-by-side ATVs and injuries related to these crashes represent an increasing percentage of the total population of ATV injury crashes. Unlike traditional ATVs, side-by-side ATVs are designed to carry two passengers abreast and usually include roll bars and seat belts. Most side-by-side ATVs are also designed to carry a limited payload in a rear cargo bed. Primary target uses for these vehicles include a combination of utilitarian tasks and recreational activities. Modifications by consumers often incorporate additional equipment that can change the mass balance and handling characteristics of the vehicle. This paper explores the resistance of these vehicles to roll as affected by the variables commonly applied to automotive crashes. Static Stability Factor (SSF) and Critical Sliding Velocity (CSV) are calculated and compared to findings from previously published work on roll resistance. Results from instrumented dynamic testing of side-by-side ATVs are presented with results for Two Wheel Liftoff Velocity (TWLV). Effects of variation in CG (center of gravity) height, track width, tire properties, suspension properties, and rider interactions are discussed as relating to rollover resistance. Results of these static and dynamic experiments provide a basis for comparison of ATV inertial properties to those published for road-going vehicles, and highlight the use of the physical pendulum for measurement of inertial properties.