This study examined the patterns of informal (unpaid) caregiving provided to people after moderate to severe traumatic brain injury (TBI), explore the self-reported burden and preparedness for the caregiving role, and identify factors predictive of caregiver burden and preparedness. A cross-sectional cohort design was used. Informal caregivers completed the Demand and Difficulty subscales of the Caregiving Burden Scale; and the Mutuality, Preparedness, and Global Strain subscales of the Family Care Inventory. Chi-square tests and logistic regression were used to examine the relationships between caregiver and care recipient variables and preparedness for caregiving. Twenty-nine informal caregivers who reported data on themselves and people with a moderate to severe TBI were recruited (referred to as a dyad). Most caregivers were female (n = 21, 72%), lived with the care recipient (n = 20, 69%), and reported high levels of burden on both scales. While most caregivers (n = 21, 72%) felt “pretty well” or “very well” prepared for caregiving, they were least prepared to get help or information from the health system, and to deal with the stress of caregiving. No significant relationships or predictors for caregiver burden or preparedness were identified. While caregivers reported the provision of care as both highly difficult and demanding, further research is required to better understand the reasons for the variability in caregiver experience, and ultimately how to best prepare caregivers for this long-term role.