This article is an attempt to create a general theoretical model or ‘scale’ for categorizing voluntary organizations chiefly concerned with social service provision. Consumer participation, which the author believes has positive and particular advantages in voluntary organizations, is taken as one element in the categorization. He discusses what participation may or should mean, and the reasons why it is so rarely found. Where it exists it tends to involve the participation of staff rather than ‘clients’, which may result in more discussion than action. The article also discusses how an organization's position on the ‘scale’ can change. Voluntary organizations which start out as small, highly-participating, self-help organizations tend to become more elitist and altruistic with success and growth. The author suggests that organizations with a higher degree of consumer participation may be more responsive to social change and its consequences, more flexible and even more cost-effective than more traditionally organized institutions and may also be better able to take advantage of the independence afforded only to voluntary organizations in an increasingly state-dominated society.