This study focuses on principals' responses regarding documentation of special educational needs (SEN) in Swedish preschools. The curriculum allows large scope for principals to interpret and implement SEN documentation, which raises questions about values, knowledge, and processes that steer SEN documentation. According to the curriculum, the aim of documentation is to evaluate and analyse the education. However, research suggests that practitioners are uncertain about documentation in relation to SEN (Renblad & Brodin, 2014) and that documentation more often focuses on children than on evaluating the education (Lutz, 2009; Palla, 2018). This study draws on Schön's (1995) theoretical framework regarding professional knowledge as co-constructed through reflective processes in preschools and in relation to principals as agents. Following an interpretive paradigm, ten in-depth interviews were conducted with principals of Swedish preschools. The interviews were analysed through a thematic approach (Cohen et.al, 2011). The principals were provided with written information about the study and gave their written informed consent before the interviews. The data was anonymised, and all the ethical requirements of the Swedish Research Council were followed (SRC, 2017). Even though all principals in the study work towards the goal of an inclusive preschool, the analysis reveal three main positionings towards documentation (resisting, accepting, enthusiastic). The positionings are characterised by different views on: The value of documentation; The space for reflection in the documentation process; The principals' own role in coordinating, structuring, and evaluating documentation. The findings are important for understanding how to improve SEN knowledge management in preschools.