BACKGROUND Previous studies on (GDM) focused on finding new strategies to decrease the incidence of its complications; however, there is insufficient evidence that investigate the influencing factors of adherence to healthy behaviors. This study examined the influencing factors of adherence to healthy behaviors among pregnant women with gestational diabetes (GDM). METHODS Descriptive cross-sectional design was used among pregnant women with gestational diabetes. The study participants completed study instruments twice (pre-test & post-test), with a four-weeks gap. The measurement scales included summary of diabetes self-care activities measure (SDSCA), diabetes management self-efficacy scales (DMSES) and open-ended questions to assess barriers and motivators of adherence. The analytical tool was multiple linear regression. RESULTS The results from multiple regression indicated that 20.0% of the total variation in the adherence to healthy behaviors was explained by women's perceived self-efficacy and the overall relationship was significant [F (1, 88) =23.60, P<0.000]. From the demographic variables, only, the gestational age at delivery was found to be a significant predictor of adherence to healthy behaviors (t=-3.1, P<0.05), adjusted R-square =15.6. Physical limitation and time constraints (40%) were the most reported barriers for adherence. Participants' concern of GDM-related complications (94.4%) and family moral support (52.2%) were the main identified motivators for adherence. CONCLUSIONS The importance of assessing determinants, barriers and motivators of adherence to healthy behaviors should be considered before planning any antenatal health promotion interventions designed for women with GDM. The study findings have implications for research, practice, policy advisors and public health. For practice, maternal nurses should consider the identified barriers in this study in any health education intervention and provide solutions and resources to the pregnant women to overcome these barriers. Policy advisors need to take into considerations providing pregnant women with flexible working hours that could encourage them maintaining healthy lifestyle behaviors during the pregnancy period. Researchers interested in GDM should examine in the upcoming studies different self-efficacy enhancing strategies among pregnant women with GDM.