In this article we examine the relation between variation theory and Maria Montessori’s didactic theory. Montessori believed that training and sharpening of the child’s senses are crucial for their continued learning; she therefore developed specific sensorial materials to be used in Montessori preschools for such a purpose. As noted by interpreters of Montessori education, a key principle in this material, as well as in variation theory, is the use of variation and invariance. However, in this article, lessons in two different areas than the training of the senses are analysed from a variation-theoretical perspective on learning; these lessons originate from Montessori’s own writings and from extracts from Montessori training courses. The result shows that a systematic use of variation and invariance can be seen as a more fundamental part of Montessori’s didactic theory and is not only applied in the sensorial training. The article will offer theoretical concepts useful when explaining why lessons in various areas should be presented in the way they are described.