Background: Due to migration processes, cultural diversity and strangeness are becoming characteristics of modern society. The competence to handle this heterogeneity--the so-called intercultural competence--is a key competence for all children and youths. Sports and physical education (PE) are often considered as a particular field for enhancing intercultural competence. However, until now there is no theory-based empirical study that proves this assumption. Purpose: This study was designed to examine the effects of a standardised, theoretically driven programme in PE on the development of underlying cognitive concepts of intercultural competence: acculturation attitudes and attitudes towards cultural diversity. Research design: The research design consists of a quasi-experimental design with four measurement points. The intervention group (N = 69; mean age = 11.6 years (SD = 0.60)) followed standardised and theory-driven intervention lessons following the didactical guidelines of the concept of "Intercultural Movement Education" (IME). The developed games tend to trigger 'crises' with the aim to insecure students. These experienced insecurities were afterwards reflected upon with the students. The internal control group (N = 63; mean age = 11.8 years (SD = 0.62)) and external control group (N = 93; mean age = 10.8 years (SD = 0.69)) were taught in a unspecific manner. The impact of the intervention study programme was tested with a reliable and valid questionnaire. Results: A significant time by group interaction effect for the subscale "assimilation/segregation" of acculturation attitudes was found in boys and in girls. The attitudes increased significantly after the intervention. For the girls, the intervention group showed also a significant decrease of the attitude "integration." No significant impact of the intervention study on the attitudes towards cultural diversity could be identified either with boys or girls. Discussion: The effects of the study are ambivalent. The significantly increased assimilative attitudes can be interpreted as a need for a sense of security. This is also underlined by the decrease of the integration attitude that values the maintenance of cultural integrity. It must be critically discussed whether the "crises" were too intense and not adapted to the children's skills to overcome them. Second, we have to critically analyse whether the discussions with the students about their experiences were sufficiently focused to debrief the students. Summary for practitioners: The competence to handle heterogeneity--the so-called intercultural competence--is a key competence for children and youths. Sports and PE are often considered as a particular field for enhancing intercultural competence. However, until now there has been no theory-based empirical study that proves this assumption. This paper describes the development, implementation and evaluation of an intervention programme on intercultural learning in PE along the didactic guidelines of IME. This programme tries to trigger "crises" that stimulate the students to react and think about their self- and world relations. The statistical analyses show that the "crises" were probably too intense as the students' scores in assimilation attitudes increased. This lead to the didactical reflection of the implementation of intercultural learning processes in PE.