Management of multi-owner housing is never straightforward because of the need for collective homeowner action. Mancur Olson suggests that a rational individual will not participate in collective action which provides no positive net benefit for him or her. Based on this premise, it would seem that rationality drives homeowners to free-ride on othersí efforts and that, as a result, no collective action will take place. However, some homeowners do actively participate in housing management, and it is worthwhile to examine why some participate and others do not. Building on the wide-ranging applications of the collective interest model (CIM) in explaining political participation and environmental activism, this paper expands its relevance to the arena of housing management. The explanatory analysis which is based on the findings of a structured questionnaire survey in Hong Kong corroborates the central propositions of the CIM and provides a theoretical account of homeownersí willingness to participate (WTP) in housing management. In brief, the WTP is a function of beliefs about personal and group efficacy, the value of the collective good, and the selective benefits and costs of participation. These findings have far-reaching implications for the formulation of government policies promoting homeownersí active involvement in housing management in Hong Kong and other megacities.