The aim of this study is to examine the distinctive features of G.V. Plekhanov's socio-philosophical concept. The article examines his understanding of the material mode of production, the role of the geographical environment in the life of society, and the influence of Plekhanov's ideas on A. Bogdanov's concept of the identity of being and thinking. The article discusses Plekhanov's main works on this subject: “On the Question of the Development of a Monistic View of History” and “On the Materialist Understanding of History.” The scientific novelty of the study lies in the hypothesis that there was a serious difference in the materialist understanding of history between Plekhanov and Lenin. Plekhanov simplified the dialectic of productive forces and production relations, reducing everything to productive forces and underestimating the materiality of production relations. This led to the development of A. Bogdanov's concept of the identity of being and thinking. It also led to Plekhanov's misunderstanding of the new stage in the development of capitalism at the beginning of the 20th century. It also led to an exaggeration of the role of the geographical environment in the development of society.