Introduction The term defensive medicine, referring to actions motivated primarily by litigious concerns, originates from the USA and has been used in medical research literature since the late 1960s. Differences in medical legal systems between the US and most European countries with no tort legislation raise the question whether the US definition of defensive medicine holds true in Europe. Aim To present the protocol of a systematic review investigating variations in definitions and understandings of the term € defensive medicine' in European research articles. Methods and analysis In concordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic review of all medical research literature that investigate defensive medicine will be performed by two independent reviewers. The databases PubMed, Embase and Cochrane will be systematically searched on the basis of predetermined criteria. Data from all included European studies will systematically be extracted including the studies' definitions and understandings of defensive medicine, especially the motives for doing medical actions that the study regards as € defensive'. Ethics and dissemination No ethics clearance is required as no primary data will be collected. The results of the systematic review will be published in a peer-reviewed, international journal. PROSPERO registration number This review has been submitted to International Prospective Register of Systematic Reviews (PROSPERO) and is awaiting registration.