--- - |2 Abstract Why do some bouts of collective action end in bloodshed? This study evaluates a diverse collection of cases featuring opposition movements that experienced government‐led massacres. Historically, protest massacres originate to 19th century struggles associated with populational needs of obtaining public goods and political representation from governments. Unlike genocide and politicide which are likely to take place during heightened conflict, protest massacres tend to occur outside of war and civil war. Data on 76 incidents (1819–2017) capturing direct action strategies, preceding levels of mobilization, regime threat levels, and temporal characteristics of each massacre is analyzed. - 'Journal of Historical Sociology, Volume 32, Issue 2, Page 258-274, June 2019. '