Background: The Theory of Planned Behavior (TPB) is proposed to predict behavioral intention. We conducted this study aimed to investigate the effects of Suicidal Ideation (SI) and constructs of TPB on suicidal intention. Methods: This cross-sectional study was conducted with 923 married women selected by multi-stage sampling method from Gilan-e Gharb County, the west part of Iran, in 2018. Data gathering tools were a questionnaire on demographic characteristics, the Beck Scale for Suicidal Ideation, and a four-part questionnaire based on constructs of TPB, including Attitude, Subjective Norms, Perceived Behavioral Control (PBC), and Intention. Data were analyzed by SPSS 19 and AMOS using Structural Equation Modeling (SEM). Results: Out of 923 participants, 345 women (37.4%) had some degree of suicidal ideation. The mean score of suicidal ideation in all of participants was 5.98 ± 7.79, while in the 345 individuals with suicidal ideation was 15.53 ± 3.65. Suicidal ideation had the strongest positive total effect on suicide intent, while PBC and attitude had the negative effect on suicide intent. Conclusions: Since suicidal ideation had the strongest direct effect on suicidal intent, it is suggested that this variable be used for risk assessment in all suicide prevention programs and counseling measures be implemented to reduce suicidal thoughts. Also, undesirable attitudes toward suicide and perceived behavioral control on suicide intention can be considered and emphasized in planning future interventions.