Increasing health problems among children place demands on school health care. It is unclear how contextual issues, e.g. reduced resources and low priority, impact the practising of health care work within the educational system. The aim was to gain a deeper understanding of school nurses' perceptions of their opportunities for practising and handling health support work within the educational system. A qualitative study in line with constructivist grounded theory based on data from six focus group interviews with 24 school nurses. The results explain the conditions in which school nurses practise health support work within the educational system, as described in a conceptual model. The core category in the model was labelled construction of space and legitimacy for individual health support work within the educational setting. The model comprised four additional categories: experiencing restricted conditions for practising health support work; working alone and in isolation: retaining individual health support; and compromising and negotiating position and legitimacy. Interests and positions of political and organisational leaders, the school personnel and children/parents, as well as the school nurse's own strategies, constructed a limited space and legitimacy for health support work. Key words: School health care, health support, health work, school nurse, psychosocial work environment