Science teaching and particularly chemistry and physics teaching is subject to ongoing discussions concerning aims, goals and relation to modern society, as well as how to teach so that more students find physics interesting and meaningful. The need for further research on reasons why physics teaching is diverse and teaching shows different curriculum emphases have been put forward by several authors (cf. Belo, van Driel, van Veen, & Verloop, 2014; Johansson, Andersson, Salminen-Karlsson, & Elmgren, 2016). The general picture is that relationships between teachers views, curriculum emphases, classroom practices, problems and possible student shortcomings need further studies in order to generate more knowledge about the basis for teaching conditions helping students to gain knowledge and interest in physics.This study continues a line of research that has a special focus on the role of mathematics in physics teaching (cf. Redfors, 2015; 2018; Turşucu, Spandaw, Flipse, & de Vries, 2017). One strand of this research focus on students’ problems in transferring mathematical knowledge to new and applied situations during physics teaching (cf. Kuo, Hull, Gupta, & Elby, 2013). However, there is also research focusing not only problem-solving, but physics teaching in general, from the perspective of the role of mathematics skills among students, since this is viewed as important for physics learning (Angell, Lie, & Rohatgi, 2011; Uhden, Karam, Pietrocola, & Pospiech 2012; Redfors, 2015; 2018). The aim of this three-year study is to further contribute to the understanding of how relations between Reality – Theoretical models – Mathematics are communicated in different kinds of instructional situations (lectures, problem solving and labwork) in Swedish upper-secondary physics. A developed analytical framework from the pilot (Redfors 2015; 2019) is used to focus the analysis of the classroom communication on relations made (by teachers and students) between Reality – Theoretical models – Mathematics. The framework, results from an online survey to Swedish upper-secondary teachers on views of physics, mathematics and physics teaching, and results from classroom studies at upper secondary school during 2018-2019 will be reported and discussed at the conference.