To examine the relationship between service member/veteran (SM/V) traumatic brain injury (TBI) severity with caregiver health-related quality of life (HRQOL). Military treatment facility. Caregivers ( N = 316) of SM/Vs following a TBI divided into 2 groups based on SM/V TBI severity: (1) caregivers of SM/Vs following an uncomplicated mild TBI (UnMTBI Caregiver group, n = 246), and (2) caregivers of SM//Vs following a complicated mild, moderate, severe, or penetrating TBI (STBI Caregiver group, n = 70). The STBI Caregiver group was further divided into 2 subgroups: Parent ( n = 21) versus Intimate Partner ( n = 49). The UnMTBI Caregiver group consisted of intimate partners. Prospective cohort. Caregivers completed 15 HRQOL measures. Using analysis of variance and chi-square analysis, the UnMTBI Caregiver group reported worse scores on 12 HRQOL measures and more clinically elevated scores for 6 of 15 comparisons than the STBI Caregiver group. The UnMTBI Caregiver group also reported worse scores on 10 HRQOL measures than intimate partners in the STBI Caregiver group and 5 measures than parents in the STBI Caregiver group. Parents reported worse scores on 3 measures than intimate partners in the STBI Caregiver group. The UnMTBI Caregiver group reported more clinically elevated scores for 7 of 15 comparisons than intimate partners in the STBI Caregiver group. Intimate partner caregivers of an SM/V following a remote uncomplicated MTBI reported worse HRQOL than intimate partners and parent caregivers of an SM/V following a more severe TBI, mostly likely due to SM/V physical and mental health comorbidities. Interventions that focus on the SM/V's TBI and other comorbidities, the caregiver's behavioral health problems, and the relationship and family factors that interact with each other will likely have the most success in improving individual and family outcomes for military families.