We investigated a number of established and emergent antecedents of affective and normative commitment of volunteers involved with a large Australian non-profit (NP) service delivery organisation. Self-report survey data were gathered from 921 volunteers. Using multiple regression analysis, we found affective commitment was positively predicted by role scope, personal importance, organisational support, esteem-based need satisfaction and value-based need satisfaction and negatively predicted by role ambiguity. We found that normative commitment was positively predicted by socialisation experiences and congruence of organisational mission and values with personal values. Theoretical and practical implications of the findings are further discussed. Of particular note is the value of extending organisational commitment mindsets to the value-laden and idiosyncratic NP sector and its volunteers. This includes the operationalisation of constructs not traditionally included in the examination of paid staff commitment, including perceptions of personal importance and need satisfaction, to inform volunteer management practice.