BackgroundThe majority of long‐term mental health problems begin during adolescence. Low mental health literacy (MHL) may impede help‐seeking for these problems. Although MHL is a multidimensional construct and adolescent help‐seeking can be through formal and informal means, little is known about how dimensions of MHL influence these help‐seeking intentions. This study examines associations between dimensions of MHL and formal and informal help‐seeking intentions among adolescents. It also investigates whether informal help‐seeking mediates the association between dimensions of MHL and formal help‐seeking, and whether these associations are moderated by gender.MethodsA cross‐sectional survey including measures of MHL, and help‐seeking intentions was distributed to participants in 10 schools (12–17 years) across Scotland (n = 734). Data were analysed using Confirmatory Factor Analyses (CFA) and Structural Equation Modelling (SEM).ResultsConfirmatory Factor Analyses identified two distinct dimensions of MHL: ability to identify a mental health problem, and knowledge of treatment efficacy. Only knowledge of treatment efficacy was associated with increased intention to seek formal and informal help. Ability to identify a mental health problem was negatively associated with both forms of help‐seeking intentions. Informal help‐seeking mediated the association between both forms of MHL and formal help‐seeking. Gender did not moderate the associations between MHL and help‐seeking.ConclusionsCare should be taken when providing MHL interventions to ensure that adaptive forms of MHL are promoted. Future research should investigate possible mechanisms by which discrete forms of MHL influence adolescent help‐seeking as well as investigating other potential moderators of MHL and help‐seeking, such as stigma.