The present study aimed to establish the associations between hopelessness, depression and impulsivity with respect to suicidal ideation and behavior, and to explore the role that impulsivity plays in the mechanism that operates between depression and hopelessness. Through an empirical observational study, with an analytical scope based on a cross-sectional design for a sample of 228 university students and using The Inventory of Suicide Orientation (ISO-30); Beck Depression Inventory (BDI); Beck Hopelessness Scale (BHS); and Barratt Impulsiveness Scale (BIS-11). The results indicated a significant positives correlations between BDI, BHS, BIS and ISO-30. Regression analysis showed that depression, impulsivity and hopelessness explain between 57% and 67% of the variance in the risk of suicidal ideation and behavior. Through the analysis of structural equation modeling, three models were established showing that impulsivity mediates the relationship between depressive symptomatology and suicidal ideation and behavior. This study has implications for mental health intervention and research, in that it emphasizes the importance of impulsivity traits as factors that act as triggers in the association between the presence of depressive symptoms and suicidal behavior.