Urban youth in Nairobi, Kenya are at risk of developing anxiety disorders due to various stressors such as poverty and environmental challenges. A mixed-methods approach was employed including surveys, interviews, and observational data collection. Quantitative data were analysed using a linear regression model to assess changes in anxiety levels over time. Among the surveyed students (n=120), those who received intervention had a statistically significant decrease in anxiety scores ($\Delta Anxious = -5.3 \pm SE(1.2)$, $p < 0.05$). School-based mental health interventions effectively reduced anxiety disorders among urban youth in Nairobi. Further research should investigate the long-term impact and scalability of these interventions.