Introduction In the United States, approximately 2.7 million grandparents have permanent custody of their grandchildren. Prevalence of primary dental caries has remained steady for those living in poverty, and among children of color. Children in the care of their grandparents frequently live in socioeconomically disadvantaged households, where dental disparities continue to exist. Research regarding the grandfamily dynamic as it relates to oral health, is limited. The purpose of this study was to investigate oral health perceptions, behaviors, and knowledge of grandparents raising/caring for their grandchildren; and explore how a grandparent caregiver’s oral health knowledge influences their perceptions/behaviors regarding their grandchild’s oral health. Methods This descriptive, cross-sectional survey research used non-probability sampling strategies to recruit grandparents who were the primary caregiver of their grandchildren, aged birth to eighteen years. A validated questionnaire was employed, both in-person and electronically. Results A total of 75 grandparents participated and answered 52% (SD = 27%) of oral health knowledge questions correctly. The study showed a correlation between low-income grandparents (M = 3.94, SD = 1.02) having higher pediatric oral health knowledge. Additionally, results indicated the greater the knowledge, the more positive intent to assist grandchildren with routine brushing and in checking their teeth for cavities. Conclusions This study demonstrated that regardless of socioeconomic status, grandparent caregiver’s oral health knowledge can positively affect their oral health-related behaviors and values, which could influence their grandchildren’s' oral health. Further research regarding grandparent caregiver utilization of public health pediatric services and dental education programs, and the potential influence of these programs on pediatric oral health, should be explored.