This chapter examines the concept of subjectivity within theoretical and philosophical psychology, tracing its marginal position in mainstream psychological discourse and its prominence in interdisciplinary debates. It reviews historical and contemporary challenges in defining subjectivity, including dualist assumptions, methodological reductionism, and the difficulty of articulating intra-, inter-, and sociosubjective processes. The chapter foregrounds selected approaches that seek to conceptualize subjectivity beyond individualistic or deterministic models, with particular attention to psychoanalysis and German Nordic Critical Psychology. It then analyzes the cultural–historical Theory of Subjectivity developed by Fernando González Rey as one contemporary response to these challenges. This framework advances an ontological understanding of subjectivity as a symbolic–emotional system and expands its scope to social processes. Rather than offering a definitive solution, the chapter positions this theory as a conceptual resource for rethinking psychological inquiry and addressing the social, cultural, and historical constitution of human life.