This study aims to examine how Swedish upper secondary teachers work with extra adaptationand special support regarding neurodevelopmental disorders (NDDs) in upper secondary schooland their perceptions of NDDs and what extra adaptations and special support entail. Tworesearch questions are presented: how do Swedish teachers define extra adaptation and specialsupport in terms of NDDs? And how do Swedish teachers work with extra adaptation andspecial support regarding NDDs in upper secondary school? Qualitative semi-structuredinterviews are conducted with six upper-secondary teachers. The results are divided into twocategories; Swedish teachers’ definition of extra adaptation and special support regardingNDDs, and the Swedish teachers’ way of working with extra adaptation and special supportregarding NDDs in upper secondary school. The results show that teachers have differentexperiences dealing with students with special needs. Moreover, teachers have a betterunderstanding of the concept of extra adaptation than the concept of special support. Therespondents give several examples of extra adaptation, such as letting students listen to music,get longer test time, opportunity to get spelling control in tests, and get material read. When itcomes to special support, the teachers link the concepts to speech synthesis, extra math lessons,or that the school procures a writing interpreter or a student assistant.