Objective: The present study was performed to determine whether lavender oil affects nausea-vomiting and anxiety in pregnant women.Methodology: In a quasi-experimental study, sixty-six pregnant women in the 6th to 16th week of pregnancy with a range of mild to moderate nausea and vomiting were randomized into two groups; a Lavender and a control group (n = 33 for each group). Twice a day (before rest in the afternoon and night sleep) for a week, samples in the intervention and control group inhaled Lavender and sesame oil, respectively. Every night before sleeping, the Rhodes nausea-vomiting questionnaire was completed by the subjects. In addition, Maternal State Anxiety (MSA) in mothers of two groups was measured by using the state anxiety scale before and on the seventh day of the intervention. Results: Seven days after inhalation of Lavender oil, the overall mean score of Rhodes index and the severity of nausea and vomiting (p = 0.008, p = 0.032, respectively), also the mean scores and severity of MSA in mothers of the Lavender group were significantly lower than the control group (p = 0.012 and p = 0.027, respectively). According to the repeated measures analysis, the mean score of the Rhodes index was significantly decreased in the Lavender and control groups during one week (p = 0.0001 and 0.004, respectively).Conclusion: This study presented evidence that Lavender aromatherapy could decrease nausea, vomiting, and anxiety in pregnant women. The findings can guide healthcare workers in providing aromatherapy to women throughout pregnancy.