Problem. Digitalisation of the professional environment necessitates the simultaneous or alternating execution of multiple heterogeneous tasks under time constraints, which brings the scientific understanding of the phenomenon of multitasking to the forefront. Despite a significant volume of research, there is no unified theoretical framework in this area, which integrates the achievements of various scientific disciplines. Aim. To systematise the main theoretical paradigms of multitasking research and analyse the psychological structure of multitasking activity. Methods. The methodological basis was a theoretical review of the literature, including peer-reviewed empirical and theoretical works indexed in the Web of Science, Scopus, PubMed, and RSCI databases, with an emphasis on recent studies and classical works that laid the foundation for the study of multitasking. Results. Five key paradigms were identified: the successive paradigm, which reveals the mechanisms of sequential information processing; the simultaneous paradigm, which emphasises the possibilities of parallelism; the resource paradigm, which interprets attention as a distributable resource; the neurocognitive paradigm, which identifies brain mechanisms; and the ecological paradigm, which considers multitasking as an adaptive mechanism. Conclusions. It was established that the psychological structure of multitasking activity includes three interrelated levels: the micro-level of switching operations, the macrolevel of coordination strategies, and the meta-level of self-regulation. The prospects of integrating ideas from different paradigms within a multilevel approach are shown, taking into account both the objective limitations of the cognitive architecture and the possibilities of overcoming them through automation, strategic organisation of activity, and metacognitive regulation.