Purpose: The purpose of this paper is to explore the components and determinants of preschool teacher organisational citizenship behaviours (OCB), i.e. role behaviours that are discretionary, unrewarded and beyond formal-role expectations. Design/methodology/approach: A total of 12 Israeli kindergarten teachers and four supervisors participated in semi-structured interviews during 2008-2009. Findings: It was found that preschool teacher OCB appears in professional (e.g. instructional innovations, diverse teaching methods, helping colleagues) and in inter-personal (e.g. the children, the parents, the local community) arenas. Likewise, both personal and organisational determinants may account for the occurrence of this behaviour in preschool teaching. Research limitations/implications: It is recommended that education districts and superintendents facilitate preschool teacher OCB by promoting greater job autonomy for kindergarten teachers and forms of participative leadership among their supervisors. Originality/value: Understanding preschool teacher OCB may fill in gaps in the theoretical knowledge about the nature of OCB among a group of employees that tends to work at small educational settings and has a limited scope of interactions with co-workers and superiors. (Contains 1 table.)