In the study, it was aimed to examine the activities in the Secondary School Mathematics Practices course books taught within the scope of mathematics practices course in Turkey and published by the Ministry of National Education, according to the principles of Model Eliciting Activity (MEA) design. For this purpose, document analysis technique, one of the qualitative research methods, was used. The data source of the study consisted of Secondary School Mathematics Practices course books (6th, 7th and 8th grades) taught since 2017. During the data analysis phase of the study, six MEA design principles (reality, model eliciting, self-assessment, structure documentation, model generalization and effective prototype principle) proposed by Lesh et al. (2000) were taken into account. According to the results obtained from the study, the principle of self-evaluation was the principle of designing the MEA that provided the lowest level of activities in the 6th and 7th grade Mathematics Practices course book. The activities in the 8th grade course book, on the other hand, scored slightly above the intermediate level in terms of the principle of self-evaluation. It was determined that the activities in the books for all three levels were more than moderately suitable for the model generalization principle, and that they were prepared in accordance with the principles of effective prototype and reality. When the activities in the course books were examined in terms of the model documentation principles, it was determined that the activities in the 7th grade course book were below the medium level, while the activities in the 6th and 8th grade course books were found to be above the medium level. As a result, it was concluded that the activities in the Mathematics Practices course books of all three grade levels generally provided the MEA design principles above the intermediate level.