The nutrition transition from traditional diets to processed snacks and sugary beverages has contributed to a higher burden of child malnutrition, obesity, and tooth decay. While child health interventions typically promote nutritious eating, they rarely promote oral health. Mothers’ motivations for child nutrition and oral health practices need to be better understood. A convenience sample of 102 mothers in eight rural Salvadoran communities participated in focus groups addressing child nutrition and oral health. Focus groups were transcribed and coded using qualitative content analysis. Primary themes included generational changes in health environments; health knowledge, attitudes, and practices; and access and barriers to health services. Mothers noted general improvements in awareness of oral hygiene but poorer child oral health, which they attributed to widespread sales of unhealthy snacks and beverages near schools. Distance and cost limited families’ access to dental services. Knowledge gaps included the belief that oral iron supplements cause tooth decay, uncertainty regarding when to start tooth brushing, and until when parents should help children brush. Maternal-child health programs should emphasize the adverse health consequences of feeding young children processed snacks and sugary drinks, and promote dental care access and regulations to ensure health-promoting environments surrounding schools.