The MA thesis deals with the basic psychological theories of learning and their application in textbooks for English and Slovene. In the theoretical part, we start by presenting the difference between learning and acquiring a mother tongue or a second/foreign language. We present the general psychological theories of learning in detail - the main characteristics of each theory, with the stress on those characteristics that are associated with language learning. We conclude the theoretical part with a definition of a textbook and a brief overview of the features that constitute a (high) quality textbook. In the empirical part of the MA thesis, we wanted to establish which psychological theories are the basis for the exercises in the textbooks for English and Slovene and which of these theories prevail. We analysed eight textbooks intended for four different user groups: native speakers of Slovene, speakers of Slovene as a second/foreign language, native speakers of English and speakers of English as a foreign language. The analysis revealed that behaviourism is still the most represented psychological theory of learning in all of the textbooks, which means that the activities are designed in a way that requires from the students the use of quite undemanding cognitive operations, such as memorization and repetition. There are also many activities that are based on the cognitive theory of learning, but it is still impossible to say that the transition from behaviourism to cognitivism has taken place; activities that encourage the use of higher cognitive processes and not just the reproduction of what has been read or heard still do not prevail.