Aims and objectives: The study aimed to examine traumatic brain injury (TBI) patient family members' (FMs) experiences of the support they received from healthcare professionals in acute care hospitals. Background: The length of hospitalisation following TBI is constantly decreasing, and patients may return home with several problems. FMs care for the patients at home although they may not be prepared for the patient's medical needs or financial burden of the illness. The burden which some FMs experience can impair patient care and rehabilitation outcomes. Therefore, FMs require support during acute phases of TBI treatment. Design: A structured questionnaire was sent to 216 TBI patients FMs. The response rate was 47% (n = 102). Methods: A structured questionnaire—based on a systematic literature review and a previous questionnaire on TBI patient FMs' perceptions of support—was developed and used in the data collection. The questionnaire included 46 statements and 11 background questions. Data were collected via an electronic questionnaire. The STROBE checklist was followed in reporting the study. Results: A factor analysis identified five factors that describe the guidance of TBI patient FMs: guidance of TBI patients' symptoms and survival; benefits of guidance; needs‐based guidance; guidance for use of services; and guidance methods. Most of the FMs (51%–88%) felt that they had not received enough guidance from healthcare professionals in acute care hospitals across all five aspects of support. Conclusions: The content of guidance should be developed, and healthcare staff should be trained to consider a FM's starting point when providing guidance. A calm environment, proper timing, sufficient information in different forms and professional healthcare staff were found to be key factors to comprehensive guidance. Involving FMs in the discharge process and rehabilitation of their loved ones both supports the abilities of caregivers and promotes the outcome of the patient's rehabilitation. Relevance to clinical practice: This study provides varied information on the need for social support of TBI patients FMs in the early stages of treatment from the FMs' perspective. This research adopted the FM's perspective to identify various areas of social support that need to be developed so that the FMs of TBI patients receive enough support during the early stages of TBI treatment.