Background: Good oral health during pregnancy can not only improve the health of pregnant women but also potentially the health of newborn. Aim: This study aimed to evaluate the effect of nursing intervention on oral health knowledge, attitude, and health behaviors among pregnant women. Design: A quasi-experimental design was utilized. Sample: A purposive sample of 188 pregnant women was recruited according to inclusion criteria. The sample was allocated to study and control groups (94 women in each group). Setting: The study was conducted at obstetric s and gynecology outpatient clinic affiliated to Benha University Hospital. Tools of data collection: 1) a structured interviewing questionnaire which consisted of three parts; demographic characteristics, obstetric history, and pregnant women's knowledge regarding oral health. 2) Pregnant women's attitude towards oral health questionnaire. 3) Pregnant women's oral health behaviors sheet. Results: The majority of both groups had poor knowledge and negative attitude regarding oral health. In addition, there were no significant differences in health behaviors scores between both groups (P > 0.05) before intervention. However, one month after intervention, 84.0% of the study group had good knowledge compared with 0.0% of the control group, 78.7% of the study group had positive attitude and only 6.4% of the control group. The health behaviors scores were significantly higher in the study group than the control (P