This chapter will draw on and interrogate a range of theoretical approaches to examining teachers’ experiences of teaching across specialisations. Teaching is a complex work, but teaching a subject without the necessary background presents its own set of challenges, both practically in the classroom and personally for the teacher. Different theoretical perspectives highlight different aspects of the experience. Four theoretical perspectives will be explored for their emphasis on where the individual teacher is placed within and how they negotiate the intersection of their practice, sense of self and the social and cultural context. The four theoretical perspectives will include Positioning Theory, Cultural Historical Activity Theory, Boundary Crossing and Lived Experience. The chapter will use research from the authors to illustrate the explanatory power of these theories in understanding the experience of teaching across subjects.