Adolescents experience numerous changes, both psychologically and physically, and they are also the age group with a high prevalence of mental problems that need counseling help. The study aims to assess the difficulties and the needs for psychological support, factors affecting the need to use psychological services among adolescents. A cross-sectional study was conducted on 672 high school students in Thu Duc City, Vietnam. The results showed that there was a statistically significant difference between grades 10–12 in student’s difficulties (DS) and a statistically significant difference in needs for psychological services (NPS, RPS). Additionally, there was a statistically significant difference in academic performance for DS. The findings also implied that RPS was predicted by a DS, NPS, and factors affecting the need to use psychological services (FA), in which NPS and DS were mediators in the relationship between FA and RPS. The study significantly contributes to research practices and the theoretical framework that the parliament and the government use to make counselors mandatory in schools. Meanwhile, the study suggested that school counselors, educators, and teachers must appropriately evaluate students' counseling needs and psychological difficulties; this is essential to providing support and interventions when students deal with challenges promptly.