Abstract: Despite the availability of evidence-based treatments, many United States veterans do not seek or complete mental healthcare when needed, which contributes to adverse outcomes such as chronic mental illness, substance misuse, and suicide. This integrative review aims to identify and synthesize the multidimensional factors that influence mental healthcare-seeking behaviours among veterans. A systematic search and synthesis of 43 peer-reviewed studies was conducted using an integrative review search. Studies were analysed to extract recurring patterns and themes related to veterans' engagement with mental health services. Five major themes emerged: military culture, need for care, barriers to care, facilitators to care, and veteran-specific care. A complex interaction of personal, cultural, and structural factors shapes veterans' mental healthcare-seeking behaviours. Addressing these barriers and enhancing facilitators through tailored interventions, culturally competent care models, and policy reforms is critical to improving access, engagement, and mental health outcomes among the veteran population.