The article is devoted to the analysis of the definition of the concepts of single mother and single parent in Russian legislation. The authors conducted a study of federal and regional regulatory and legal regulation, as well as judicial practice in the field of social protection and social security, in tax and labor relations, when bringing to criminal responsibility. To understand the genesis of the related concepts of “single mother”, “single parent”, “single parent”, the normative legal acts of the Soviet period and the historical doctrine on the problem were analyzed. As a result, it was revealed, firstly, the difference in the methods of legal confirmation of the recognition of a person as a single mother and a single parent, which manifests itself in differentiated documentary confirmation of the statuses of a single mother, the status of a single mother in a single adoptive parent, the status of a single parent in relation to the father, the status of a single parent as a single adoptive parent. Secondly, along with persons recognized as a single mother or single parent, persons raising a child without a mother or without a father due to the absence of a second parent also have a special legal status. Thirdly, in tax relations, in addition to a single mother and a single father, only the person whose second parent of children has died, is recognized as missing or declared dead, which is confirmed by relevant documents, is recognized as the single parent. Fourth, family law doesn’t create a special status of a single parent, but only defines the conditions for the emergence of such a status. In the legislation on citizenship, the concept of a single parent aims to eliminate uncertainty about the acquisition of citizenship by a child.