This study investigated the effects of depression, anxiety, and impulsiveness on suicidal thoughts among adolescents with the goal of better understanding the psychological needs of adolescents and to provide them with more effective counseling and guidance. Participants for this study included 340 high school students in their first and second year living in large urban centers. Respondents answered a questionnaire that documented their experiences related to depression, anxiety, impulsiveness, and suicidal thoughts. Data analysis was performed using the means, standard deviations, correlation analysis, and multiple regression using the IBM SPSS 19.0 statistics program. The results were as follows. There was no statistically significant difference in anxiety and impulsiveness based on gender. However, female respondents demonstrated a higher rate of suicidal thoughts than male respondents. Second, in both sexes, comparative analysis between depression, anxiety, impulsiveness, and suicidal thoughts revealed that respondents with higher levels of depression and anxiety demonstrated elevated levels of suicidal thoughts. Impulsiveness demonstrated a correlation with suicidal thoughts only for female participants. Third, while depression and anxiety affected suicidal thoughts in both male and female respondents, impulsiveness did not affect suicidal thoughts, with depression having the strongest effect.