The relevance of this article is determined by the need to study new approaches to the organization of the study of mathematics in inclusive education, explore recreational imagination, as well as self-regulation for the development of the learners’ ability to explain in detail their actions, find and correct mistakes on their own and thus develop their mathematical thinking. Today the needs of society to improve the quality of modern education along with the increasing volume of information that modern students must continuously process make the problem of developing mathematical thinking even more acute. The purpose of the study is to research the relationship between recreating imagination, mental self-regulation and mathematical thinking in students with mental retardation. Research methods included observation, psychological and pedagogical experiment, psychodiagnostic tests, and diagnostic tasks. Mathematical and statistical methods were also used (the Pearson correlation coefficient reflecting the degree of correlation between changes in two variables, where the changes in one of them correspond to the changes in the other), as well as interpretive methods. Research result: the article examines the relationship of mental self-regulation, recreating imagination and mathematical thinking in students with mental retardation and confirms the interrelationship of these processes using methods of mathematical statistics in psychology. It also discusses the complex of correctional and developmental exercises aimed at the development of recreating imagination and offers the means of developing mental self-regulation for the further development of the learners’ mathematical abilities. The data obtained in this research can be used in social psychology, pedagogy, developmental psychology, inclusive education, as well as for further theoretical development of this area and find application in the broad practice of inclusive education together with an established and experienced system of tasks.