This study assessed the association between oral health knowledge and practices of pregnant Saudi women selected from visitors to a government hospital in Dammam, Saudi Arabia in 2014. Women answered questions on oral health knowledge during pregnancy and knowledge of infant oral health. Most women (> 70%) knew that dental caries in children can be prevented, that pregnancy affects oral health and that dental treatment during pregnancy can negatively affect infants. Most women (> 80%) performed oral hygiene procedures but only 18% regularly visited the dentist. In a regression analysis, oral health knowledge was not significantly associated with reported oral hygiene practices. Women who visited the dentist regularly were more likely to know how to prevent caries in children, and that dental treatment during pregnancy and infant health were associated.