Background and Objectives: Hopelessness, belongingness, and perceived burdensomeness are important risk factors for suicidal ideation. Therefore, the aim of the present study was to determine the interaction of hopelessness, thwarted belongingness, and perceived burdensomeness in suicidal ideation and behavior. Materials and Methods:The method of the present study was descriptive and modeling. The study population included all students of Mohaghegh Ardabil University in the academic year 2020; out of which 650 people were selected using convenience sampling method and completed the questionnaires of Hopelessness, Depressive Symptom-Suicidality Subscale, Suicidal Behavior, and Interpersonal Needs in an online way. Data were analyzed using Pearson's correlation and Hayes' macro PROCESS tests. Results:The results showed a significant positive relationship between negative hopelessness and belongingness (r=0.45, p<0.001), burdensomeness (r=0.37, p<0.001), idea (r=0.32, p<0.001), and suicidal behavior (r=0.26, p<0.001). There was also a significant positive relationship between positive hopelessness and belongingness (r=0.32, p<0.001), burdensomeness (r=0.37, p<0.001), idea (r=0.25, p<0.001), and suicidal behavior (r=0.26, p<0.001). The results also confirmed the interaction of hopelessness, belongingness, and burdensomeness in suicidal ideation and behavior. Conclusion:In general, this study supports the interpersonal theory and the interaction among hopelessness, belongingness, and burdensomeness concerning suicidal ideation and behavior. Based on these findings, it is suggested, to reduce suicidal ideation and attempt, holding skills and motivation training courses can increase hope in people.