Background: Engineering students encounter high levels of stress, which may negatively impact their mental health. Nevertheless, engineering students who experience mental health distress are less likely than their peers to seek professional help, even when controlling for gender and race/ethnicity. Purpose: We examined beliefs that undergraduate engineering students have about barriers and facilitators to seeking professional help for their mental health. We also sought to identify cultural and systemic factors within and beyond engineering that might affect help-seeking. Together, these beliefs influence students' sense of personal agency around seeking mental health care. Method: We implemented a pragmatic qualitative design that incorporated the integrated behavioral model to investigate engineering students' (N = 33) professional mental health help-seeking beliefs. We used thematic analysis to analyze help-seeking beliefs and perceived barriers and facilitators that students described during interviews. Results: We identified four themes: Navigating the system impacts personal agency; sacrifices associated with help-seeking act as a barrier; engineering culture acts as a barrier to help-seeking; and student confidence in help-seeking varies significantly. These themes portray the effect of perceived barriers and facilitators on students' personal agency for accessing mental health care. Our findings have implications for engineering departments and university counseling centers that want to minimize barriers to help-seeking. Conclusions: Engineering stakeholders must improve access to professional help for engineering students. Implementing changes to normalize help-seeking behaviors, enhance personal agency, and facilitate engagement with mental health resources will create better conditions for engineers. Further research is necessary to understand how other beliefs (e.g., attitudes, perceived norms) inform the relationships between student mental health, professional help seeking, and engineering culture.