This article reports on physics teaching in upper-secondary school with a focus on communication and relations made between mathematics, theoretical models in physics, and reality. Video data from four physics classrooms in three different teaching contexts, i.e., lessons, problem solving, and lab work, have been analysed by combining two theoretical frameworks: the Ternary Framework and Joint Action Theory in Didactics. Four physics teachers were selected from among a range of teachers who had responded to a web-based questionnaire, representing different teacher profiles from the questionnaire. The results indicate that the teacher profiles, including information on curriculum emphasis and views of mathematics, physics, and physics teaching, were good predictors for communication in the classrooms. The teacher profiles were found to influence teaching and the communication more than the teaching contexts. The benefits of formally correct mathematical treatment during physics teaching are discussed based on the results.