During pregnancy, women are more susceptible to certain oral disorders, which may have a negative impact on either mother or child health. Oral hygiene and related negative prenatal outcomes are often neglected issues, particularly in underdeveloped countries such as Pakistan. Objective: To assess the knowledge and practices of oral hygiene among pregnant women at tertiary care hospital. Methods: This cross-sectional study based on questionnaire was carried out at the Dental unit of Khyber Teaching Hospital, Peshawar for a period of one year from July, 2020 to December, 2021. A total of 400 pregnant women were included in this study. Their knowledge level and practices about oral health were determined by using proper designed questionnaire. All the data analysis was performed by using SPSS version 22. Results: In our study, 308 (77%) subjects consider sugar as the cause of dental carries while 92 (23%) subjects does not consider sugar as the cause of dental carries. Among 400 subjects, 140 (35%) subjects consider sugar as the cause of gum disease. Concerning oral hygiene practices, 360 (90%) subjects use tooth brush. The number of subjects using tooth brush daily, twice or more than twice were 280 (70%), 112 (28%) and 8 (2%) subjects respectively. Conclusion: Our study concludes that most of the pregnant women in our study were knowledgeable and have good practices but there is still a gap in their level of knowledge and practices. It is essential to provide oral health education for management of good oral health during pregnancy.