<p style="text-align: justify;">The article reviews of a number of modern foreign studies of emotion differentiation and its role in emotion regulation processes. An attempt is made to generalise the currently existing results on the connection of emotional differentiation with various personality and behavioural constructs, as well as about its role of in psychological well-being. The main advantages of high negative emotional differentiation and disadvantages of low negative emotional differentiation are identified. Trait and momentary emotional differentiation was distinguished, difficulties in conceptualising and measuring the momentary emotional differentiation were outlined, the lines of future studies of the relationship between both measures of emotional differentiation and emotion regulation were described. Several studies of the role of emotional differentiation in the choice and effectiveness of putatively adaptive and maladaptive emotion regulation strategies were analysed. It was found that higher levels of negative emotional differentiation were related to the effectiveness of emotion regulation strategies rather than to their choice. Similarities and differences in the methodology and obtained results of the analysed studies are identified. Issues requiring further research are formulated, prospects for future research are described. The practical significance of the research findings for the use in psychotherapy and treatment of psychological disorders is outlined.</p>