Six psychographic segments of volunteers in Australia are constructed on the basis of their volunteering motivations. The resulting segments include classic volunteers, whose motivations are three-fold: doing something worthwhile, personal satisfaction, and helping others. Dedicated volunteers perceive each one of the motives for volunteering as relevant, while personally involved volunteers donate time because of someone they know in the organization, most likely their child. Volunteers for personal satisfaction and altruists primarily wish to help others, and finally, niche volunteers typically have fewer and more specific drivers motivating them to donate time, for example, to gain work experience. The segments are externally validated and demonstrate significantly different socio-demographic profiles. Consequently, it seems that motivation-based data-driven market segmentation represents a useful way of gaining insight into heterogeneity amongst volunteers. Such insight can be used by volunteering organizations to more effectively target segments with customized messages.