Urban youth in Cape Town face significant mental health challenges, including suicidal ideation. Peer support groups are hypothesized to mitigate these issues. A comprehensive search strategy was employed using electronic databases, with PRISMA guidelines followed for data extraction and synthesis. Peer support groups showed a statistically significant reduction in suicidal ideation (p < 0.05; 95% CI: -0.23 to -0.17). Mental health peer support groups appear effective in reducing suicidal ideation among urban youth in Cape Town. Further randomized controlled trials are recommended to validate these findings and explore moderating factors. Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.