Attacks on health care in armed conflict, including those on health workers, facilities, patients and transports, represent serious violations of human rights and international humanitarian law. Information about these incidents and their characteristics are available in myriad forms: as published research or commentary, investigative reports, and within online data collection initiatives. We review the research on attacks on health to understand what data they rely on, what subjects they cover and what gaps exist in order to develop a research agenda going forward.