This article deals with an educational practice that involved mainstreaming students taking Swedish as a second language and others taking Swedish as a first language. It explores the fiction-reading teaching practice in this mainstreaming framework, a matter of which has been intensely debated internationally. Three upper secondary classes and four teachers were involved and the empirical data consists of interviews and classroom observations. The analysis is built on the theory of practice architecture and captures a set of three arrangements; cultural-discursive, material-economic and social-political, and seeks to illuminate the associated opportunities and obstacles. The teachers’ balanced approaches were found to be enabling while constraining aspects emerged in relation to, among other things, unclear policy documents. The theory not only helped identifying the complexity of implementing a mainstreamed classroom, but also the benefits arising from teachers who took a praxis approach.