Social constructivism in the international relations theory (IRT) is the youngest paradigm, which, together with neorealism and neoliberalism, is one of the three most popular theoretical patterns among international specialists. This paradigm explains global transformations and regional noticeable changes by studying the social construction of international reality. Key concepts in constructivism are identity, which shapes the interests of international actors, and intersubjectivity in cross-border relations. Constructivism in IRT considers norms as a factor that constitutes the role and standards of behavior that influence the identity and choice of participants in the global political process. The understanding of norms changes over time, which causes the instability of international relations. However, anarchy in international relations for constructivists is not inevitable; instead it depends on different cultures and practices. The main variants of the classification of social constructivism in IRT are considered. Leading reviewers, as a rule, divide the constructivists into three conditional groups, separately mentioning the Copenhagen School. The first group, “neoclassical constructivism”, according to John Ruggie, included followers of Durkheim and Weber. The second group, “postmodern constructivism”, had roots in Nietzsche’s irrationalism and Foucault’s poststructuralism. The third group, “naturalistic constructivism”, rejected necessity of choosing between internal and external interpretations of social action and social order. Emanuel Adler identified groups of “neoclassicists”, “linguistic modernists” and “supporters of compromise synthesis” among the constructivists. Branching out in several directions, constructivism was very popular in IRT in the first decade of the 20th century, but in the last decade it lost a significant part of its supporters in the struggle with other theories for influence in the discipline. That is why the supporters of the development of the science of international relations at the expense of its further sociologization intensified attempts to renew constructivism. Efforts are being made to develop social constructivism due to the introduction of IRT based on relationalism, practice theory and actor-network theory, which David McCourt tries to use in the book “The New Constructivism in International Relations Theory”. The supporters of a new constructivism in IRT prefer to see the improvements in the appearance of a number of practical constructivist empirical studies tangential to the practice theory, among which the most recent books by Mark Raymond, Mark Shirk and Ayşe Zarakol, working mainly in the genre of historical sociology. The work of neoconstructivist enthusiasts deserves the attention of IRT specialists and the subsequent restrained demand of the public, because it needs the elimination of methodological inconsistencies and reinforcement with serious empirical data from related disciplines.