Teaching foreign languages to people of all ages is based on didactic approaches and didactic and methodological principles, however, due to the age peculiarities of children and adults, these approaches and principles should be applied differently. The purpose of this article is to determine approaches and principles for the development of children’s and adults’ foreign language communicative competence. The article discusses modern approaches to teaching a foreign language, such as personal-active approach, competence approach, systematic approach and communicative approach. Some peculiarities related to working with children and working with adults that should be considered when applying these approaches are mentioned. The article presents a comparative table that reveals the similarities and differences of the following didactic principles: the principle of consciousness, scientific character, quality of retention, systematicity and consistency, activity and self-reliance, accessibility, visibility, unity of education and upbringing. The methodological principles (orientation on speech, individual and personal characteristics and interests of students, functionality, situationality, novelty) which the teaching of foreign languages to children and adults should be based on in order to develop their communicative competence are defined. Possible difficulties that arise when teaching a foreign language are indicated. The results of the study can be used in practice by foreign language teachers working with both children and adults.