Patients frequently depend on informal caregivers (e.g., family, friends, or paid workers) to assist with various aspects of medical care, such as medication administration and travel to medical appointments. OpenNotes seeks to share clinicians' notes with patients through patient portals. Although patients frequently grant portal access to caregivers, the impact of this improved access to health information on the safety of care provided by caregivers remains unknown. Researchers sent a survey to 24,722 patients participating in OpenNotes who had at least one available visit note during the study period. The surveys were sent through the patient portal. Out of the 7058 surveys returned, 150 respondents self-identified as caregivers. Analysis of survey data revealed that access to patient notes enhanced caregiver understanding of recommended medical care including tests and referrals, reminded them about necessary testing, helped them understand results, reminded them about appointments, and improved caregiver ability to assist patients with medications. An Annual Perspective discussed the potential of health information technology to improve patient and caregiver engagement in safety.