Objective: To examine the association between mental health workforce supply and spatial clusters of high versus low incidence of youth suicide. Methods: A cross-sectional analysis of spatial suicide clusters in young Australians (aged 10–25) from 2016 to 2020 was conducted using the scan statistic and suicide data from the National Coronial Information System. Mental health workforce was extracted from the 2020 National Health Workforce Dataset by local government areas. The Geographic Index of Relative Supply was used to estimate low and moderate-to-high mental health workforce supply for clusters characterised by a high and low incidence of suicide (termed suicide hotspots and coldspots, respectively). Univariate and multivariate logistic regression was used to determine the association between suicide clusters and a range of sociodemographic characteristics including mental health workforce supply. Results: Eight suicide hotspots and two suicide coldspots were identified. The multivariate analysis showed low mental health workforce supply was associated with increased odds of being involved in a suicide hotspot (adjusted odds ratio = 8.29; 95% confidence interval = 5.20–13.60), followed by residential remoteness (adjusted odds ratio = 2.85; 95% confidence interval = 1.68–4.89), and illicit drug consumption (adjusted odds ratio = 1.97; 1.24–3.11). Both coldspot clusters occurred in areas with moderate-to-high mental health workforce supply. Conclusion: Findings highlight the potential risk and protective roles that mental health workforce supply may play in the spatial distributions of youth suicide clusters. These findings have important implications for the provision of postvention and the prevention of suicide clusters.