Quantification of the mechanical properties of cured sealant is complicated by the presence of the Mullins effect. This paper examines the Mullins effect using five different sealants encompassing the range of properties and formulations found in commercial sealants. Three main observations include: the Mullins effect was observed in all sealant formulations studied, the Mullins effect was observed in both tension and compression strains, and there was a recovery of the Mullins effect after sufficient periods of time between repeated loading cycles. Simple rules were formulated to describe the Mullins effect. Moreover, the tests show that understanding the Mullins effect is crucial in characterizing the mechanical properties of a sealant.