Mental health is a core component of overall wellbeing and can contribute to positive functioning and purpose in life. Mental health is purportedly related to the constructs of generalised self-efficacy (GSE) and health locus of control (LOC). Most research, however, has explored GSE and LOC and their relationship with psychopathology, or defined mental health as a lack of psychopathology indicators. This contradicts the two continua model of mental health, as it does not incorporate positive mental functioning. The current study sought to re-examine the relationship between health LOC, GSE, and mental health, whilst controlling for potential confounding factors. It was anticipated that health LOC and GSE would predict mental health. A sample of 224 adults completed an online survey comprised of validated psychometric tools scales. Regression analyses were conducted to determine whether health LOC and GSE predicted mental health, after controlling for self-esteem, social support, and coping. Results indicated that GSE was a significant unique positive predictor of mental health. Health locus of control was not a significant predictor of mental health. Limitations were present, including a cross-sectional research design and use of convenience sampling. This study builds upon existing research in providing a better understanding of contributors to mental health, which may assist in the development of evidence-based mental health promotion interventions.