Purpose: The purpose of this paper is to examine whether individuals who prefer different volunteering organisations have different self-concepts, whether individuals perceive their preferred volunteering organisation as more similar to their self-concept than other volunteering organisations, and whether self-congruity theory correctly predicts consumer (volunteer) behaviour differences across organisations and organisational missions. Design/methodology/approach: Data were collected on people's preferred volunteering organisation, their self-concept and their perceived image from eight volunteering organisations using an online self-completion survey. Chi-square tests and paired-sample t-tests were then used to identify significant differences between groups. Findings: Individuals who prefer different volunteering organisations differ significantly in their self-concept. For the three volunteering organisations with high levels of awareness and distinct images, self-congruity theory held; that is, people who volunteer for them perceive those organisations as being more similar to their self-concept than other volunteering organisations. For the four organisations with lower awareness and less distinct images, the authors found a tendency towards self-congruity, but results were not significant. In one case, self-congruity theory did not hold, possibly due to the more "obligatory" nature of the volunteering task. Research limitations/implications: This research extends the application of self-congruity theory to the volunteering context. It identifies three key dimensions that affect the extent to which self-congruity holds for volunteering organisations: brand awareness; image distinctiveness; and whether the involvement is actually "voluntary". Practical implications: Self-congruity theory has the potential to be a valuable tool in helping volunteering organisations increase their productivity through better targeted marketing strategies. Originality/value: This study is the first to apply self-congruity theory to the volunteering sector at the organisation brand level, and gives practitioners an additional tool to improve the effectiveness of their marketing.