This paper examines the entangled relationship between Russian Orthodox missionary activity and the broader movement promoting church reform and conciliarity within the Russian Orthodox Church between the 1880s and the Moscow Council of 1917-1918. It traces the influence of changing understandings and practices of conciliarity on the way that mission was understood, contested and defined at late imperial episcopal assemblies, missionary conferences and the Moscow Council itself. The paper demonstrates how we see in the resolutions on mission of the revolutionary period and at the Moscow Council, an increasing conciliar emphasis on the engagement of laypeople and the entire church community in shaping the contours of the Church's witness, as opposed to colonial views of mission linked with imperial expansion and the integration of new subjects into the social fabric of the Russian Empire.