This article investigates the relationships between particular social trust, general social trust, and political trust and tests a variety of political, social-psychological, and social capital theories of them. This sort of research has not been carried out before because until the World Values Survey of 2005–07 there has been, to our knowledge, no comparative survey that includes measures of particular and other forms of trust. The new data challenge a common assumption that particular social trust is either harmful or of little importance in modern democracies and shows that it has strong, positive associations with other forms of trust. However, the relationships are not symmetrical and particular social trust seems to be a necessary but not sufficient cause of general social trust, and both forms of social trust appear to be necessary, but not sufficient conditions for political trust. Strong evidence of mutual associations between different forms of trust at both the individual micro level and the contextual macro level supports theories of rainmaker effects, the importance of political institutions, and the significance of social trust for political trust. In more ways than one, social trust, not least of a particular type, seems to have an important bearing on social and political stability.