The concept of flexibility has received widespread attention beyond its theoretical roots in manufacturing. It has been applied to the services sector, including tourism and hospitality; however, little work has investigated the transference of its basic tenets to volunteering. Research is lagging behind practice in contemporary volunteering as the value of flexible attitudes and flexible work options in terms of recruitment and retention outcomes is increasingly recognised. To address this gap, the current paper proposes a conceptual model that takes into account levels of reciprocal flexibility between host organisations and their volunteers, against the backdrop of volunteer supply. A comprehensive explanation of the literature supporting this model and its accompanying research questions serve as a way forward to determine whether all types of tourism organisations, offering a range of volunteering opportunities, need to be flexible in order to recruit and retain volunteers.