The purpose of this study has been to contribute to an increased understanding of how specialist teachers and subject teachers co-teach in the ordinary classroom and work together with students in need of special support and to investigate which different forms of co-teaching occur when teaching language, reading and writing in elementary school. The study also aims to illustrate the special needs teachers' and teachers' perceptions of the collaboration in co-teaching and how the teachers perceive the concept of inclusion and how the specialist teacher's competence is perceived. The study was carried out through two classroom observations of co-teaching between two subject teachers an two unauthorized specialist teachers, and through follow-up semi-structured interviews with said teacher pairs. To further add a specialist teacher perspective, two qualified specialist teachers specialized in language, reading and writing development were interviewed. The observations that should be seen as a complement to the interviews are presented narratively through a descriptive text (Bryman, 2018). The interviews were transcribed and analyzed using phenomenographic analysis in seven steps (Fejes, 2017). An additional analysis was made from a social constructionism perspective where links to central concepts such as relationships, communication and interaction were made (Burr, 2015); Dysthe, 1996; Emanuelsson, Persson and Rosenqvist, 2001; Persson, 2019). All teachers in the study have experience of co-teaching, however, the results point to a lack of common language for describing co-teaching and its different forms of work. Furthermore, the results show that the respondents saw that co-teaching can help the specialist teacher to get to know all the pupils and all the educators and that co-teaching becomes more varied as it is carried out by two teachers who complement each other. Another positive effect that emerges from the study is that co-teaching can contribute to extra adaptions becoming a natural part of the regular teaching, which could contribute to a more inclusive classroom climate.