Background: Men account for 75% of all suicide deaths in Australia. Societally dominant masculine norms have been theorized to be linked with suicidality and reduced help-seeking. However, evidence is needed to establish this relationship further. Aims: To further understand the relationships between 11 masculine norms, suicidal ideation, and mental health help-seeking behavior longitudinally in Australian males. Method: We analyzed data from a cohort of 8,214 males (aged 18-55 years), using logistic regression to examine if conformity to any of the 11 masculine norms measured by the Conformity to Masculine Norms Inventory (CMNI-22) at Wave 1 was associated with suicidal ideation and help-seeking at Wave 2. Results: Analyses revealed that being in the high conformity group for the norm of emotional control at Wave 1 was associated with higher odds of suicidal ideation longitudinally. Being in the low conformity group for the global construct of masculine norms and the specific norms of emotional control and power over women was associated with higher rates of mental health help-seeking behavior longitudinally. Limitations: The CMNI-22 scale's limited construct validity and the use of a single-item measure for suicidal ideation may have restricted the accurate capture of masculine norms and suicidal behaviors in Australian men. Conclusion: These results provide support for the contention that suicidality is a profoundly gendered phenomenon by showing an association between masculine norms and suicidal ideation in men. These norms should be a point of focus of male suicide prevention initiatives.