Forty years of research has established bullying as a globally pervasive, adverse experience associated with a multitude of immediate and longer-term negative life outcomes. The school is identified as a site with a high concentration of bullying. As a result, a number of school-based anti-bullying interventions have been developed and implemented with the hope of reducing overall prevalences of the behaviour and negating its negative impact on a new generation. KiVa is one such school-based anti-bullying programme, developed and designed for national use in Finland in 2006. KiVa has since been subject to a number of cross cultural investigations of transferability, efficacy and success. To date, however, KiVa research, including several UK based studies, has been solely conducted in mainstream primary school settings. As a result, there are no reports on the use of the programme with a population of students with additional learning needs, despite evidence that these students are particularly vulnerable to both being bullied, and bullying others. The present case study is an attempt to address this gap in the literature, and follows the implementation of KiVa (Unit 1) over one academic year in the middle department (n = 46, ages 12 - 15) of a large special school in North Wales. Qualitative and quantitative data from teachers implementing the programme and students in receipt of the programme are included. Teachers participated in semi-structured interviews, and completed weekly Teacher Lesson Records as a measure of implementation fidelity, and a final Teacher Survey at the end of the academic year to explore their final perceptions of the programme. Students completed the online pre-and post-KiVa Pupil Survey, and ten students were invited to participate in focus groups at the end of the academic year. The research has two central aims; the first, to assess the feasibility of implementing KiVa in this novel setting and document any adaptations necessary for implementation, and the second, to investigate programme impact on students with additional learning needs in this setting, together these aims help to determine the acceptability of KiVa in this novel setting. Though feasibly implemented in this setting, KiVa required a number of minor adaptations to improve intervention-setting-fit, and a number of more fundamental programme changes which may have negatively impacted programme success and student outcomes. Declines in students perceptions of school climate and increases in student self-reported victimisation and cyber victimisation are observed, however teachers believed that KiVa also led to positive developments in terms of students personal, social and emotional learning, and may therefore meet positive though unintended needs of this student population. Results suggest
mixed acceptability in this setting. Limitations of the present research are discussed, followed by avenues of future research raised by the results gathered.