ABSTRACT Background Science, Technology, Engineering, and Mathematics (STEM) industries are competitive and can be stressful work environments leading to an increase in substance misuse. Little is known on the role of work-related risk and protective factors on substance misuse among working parents navigating multiple roles. Objectives This study aims to examine work-life balance as a protective factor and various risk factors (emotional exhaustion, work-family, family-work conflicts) for hazardous alcohol use and increased risk for prescription drug misuse among diverse working parents in STEM. Methods Participants (n = 1,228) were recruited via Qualtrics from across the US and the sample was racially ethnic and gender (50% men, 50% women) diverse. An overall path analysis was conducted to explore direct and indirect effects of work-life balance on hazardous alcohol use and increased risk for prescription drug misuse. Path analyses explored the racial-ethnic and gender differences across the overall model. Results Path analysis revealed that healthy work-life balance indirectly predicts decreased hazardous alcohol use (b = −.149, p = .004) and decreased risk for prescription drug misuse (b = −.185, p < .001). Exploration of the model across racial-ethnic and gender groups revealed that higher work-life balance indirectly predicts decreased hazardous alcohol use for Black and Asian Americans, but not for Latinos and Whites; and higher work-life balance indirectly predicts decreased hazardous alcohol use for men, but not women. Conclusions Identifying the work-family interface can help providers understand prevention, risk-reduction practices, and interventions for hazardous alcohol use and prescription drug misuse among diverse working parents in STEM.