This thesis investigates the potential influence of English as a medium of instruction in Geography lessons for content teaching. The research focuses on the teacher and the di-verse facets and factors which are closely linked to the implementation of bilingual Geog-raphy teaching. Due to interdependences between teaching and learning, the latter is also taken into account.The thesis is divided into two parts: one theoretical and one empirical. The first part pro-vides a theoretical overview on the topic, dealing with aspects such as progression, rea-sons, goals, and different forms of the implementation of English as a medium of instruc-tion. Additionally, crucial factors of the general and legal framework are discussed. Then the connection between English as a medium of instruction and the content subject Geogra-phy is established, and the suitability of the content subject is discussed. In the following chapter, methodological scaffolding models and didactic teaching principles are illustrat-ed to show the practicality for content and language integrated teaching in Geography. The final theoretical chapter considers interconnections and disparities between content and lan-guage integrated learning and teaching on a cognitive, content, and language level.The seventh chapter deals with the empirical part of the study. Ten interviews with two expert groups in eight academic secondary schools (AHS) in Styria were conducted eight interviews with Geography teachers concerning repressive and fostering factors that influence bilingual Geography teaching, and two interviews with principals regarding implementation of English as a medium of instruction in the school system. It is hoped that this study will encourage further investigation of English as a medium of instruction in content subjects, since the concept has not yet been fully developed in Aus-tria.