The main aim of the present study is to reveal the relationship between a 4th-grade EFL textbook used in Turkiye and the mediation notion that is given a place in the Companion Volume to the CEFR (CEFR/CV) in 2018. The deductive thematic content analysis method of qualitative research, including techniques such as re-reading and taking notes, was conducted to analyze the data coming from the data collection process. Textbook activities were unpacked and coded under themes that were determined beforehand. Then, illustrative descriptors for mediation from the CEFR/CV were extracted and coded. Mediator activities found in the textbook and illustrative descriptors of mediation were comparatively analyzed to reveal the extent of their match. Themes were created out of the illustrative descriptors for mediation from the CEFR/CV, and textbook activities were unpacked and categorized in the light of these themes with their IDs that were determined before. Finally, an expert in the field receives a second opinion on the themes, categorizations, and coding processes. Descriptive analysis displayed the relationship between the textbook and mediation characteristics in the CEFR/CV. The results show that most textbook activities do not reflect the characteristics of mediation mentioned in the CEFR/CV. There were 14 mediator activities out of 168 indicate mediation, constituting 8,3% of the textbook. There were also other mediators found in the textbook such as visual and audial aids.