Background: The transition from childhood to adolescence is associated with suicidal ideation (SI) and feelings of hopelessness. The aim of this study was to investigate the prevalence of SI and hopelessness (and relevant family factors) among adolescents in southern Mexico studying in public and private high schools. Methods: A significant sample of high school students (15-19 years old) was taken in the city of Tuxtla Gutiérrez, the State of Chiapas, Mexico. The Beck scale for SI, the Beck hopelessness inventory, and a survey of family data were applied to adolescents, 364 in public and 240 in private high schools. Results: The teens in public schools showed a higher prevalence of hopelessness (32%) and SI+hopelessness (10%). In both public and private schools, these attitudes were more common among women as well as teens from small (3-4) families and those without a job. Conclusions: The behaviors found among teens of public and private high schools suggest the importance of a lack of family stability and economic solvency in the development of suicidal behavior. The present results may be useful in formulating strategies to prevent suicide.