OBJECTIVE: Nutritional disorders during pregnancy negatively affect maternal and fetal health, causing low birth weight, prematurity, and mortality. The aim of this study is to determine the prevalence and associated factors of orthorexia nervosa among pregnant women in Turkey. METHODS: A descriptive and correlational research design was used. The study was conducted between August and October 2023. The research population consisted of pregnant women who came to a public hospital in the north of Turkey for routine pregnancy follow-up, and the sample included 417 individuals who volunteered to participate in the research and were selected using the sampling of the known population method. Study data were collected using a Personal Information Form and the ORTO-11 Scale, and chi-square test, Binary Logistic Regression analysis were employed to analyze the data. RESULTS: In our study, the prevalence of orthorexia nervosa during pregnancy was found to be 8.9%. There were significant positive associations between orthorexia nervosa and lower education level [AOR (Adjusted odds ratio):0.117, 95% CI (Confidence interval): (0.015-0.972)], higher physical activity frequency [AOR:4.166, 95% CI: (1.270-13.553)], and unplanned pregnancy [AOR:7.865, 95% CI: (2.630-23.515)]. CONCLUSIONS: In conclusion, it was determined that approximately one in every eleven pregnant women experienced orthorexia nervosa and the level of education, frequency of physical activity, and pregnancy planning status of pregnant women affected it. It is very important for health professionals to provide education about nutrition during pregnancy and to determine eating disorders at an early stage for the health of the mother, fetus, and society.