The importance of social trust has become widely accepted in the social sciences. A number of explanations have been put forward for the stark variation in social trust among countries. Among these, participation in voluntary associations received most attention. Yet, there is scant evidence that participation can lead to trust. In this paper, we shall examine a variable that has not gotten the attention we think it deserves in the discussion about the sources of generalized trust, namely equality. We conceptualize equality in two dimensions: one is economic equality and the other is equality of opportunity. The omission of both these dimensions of equality in the social capital literature is peculiar for several reasons. One is that it is obvious that the countries that score highest on social trust also rank highest on economic equality, namely the Nordic countries, the Netherlands, and Canada. Secondly, these are countries that have put a lot of effort in creating equality of opportunity, not least in regard to their policies for public education, labor market opportunities and (more recently) gender equality. The argument for increasing social trust by reducing inequality has largely been ignored in the policy debates about social trust. Social capital research has to a large extent been used by several governments and policy organizations to send a message to people that the bad things in their society are caused by too little volunteering. The policy implication that follows from our research is that the low levels of trust and social capital that plague many countries are caused by too little government action to reduce inequality. However, many countries plagued by low levels of social trust and social capital may be stuck in what is known as a social trap. The logic of such a situation is the following. Social trust will not increase because massive social inequality prevails, but the public policies that could remedy this situation can not be established precisely because there is a genuine lack of trust. This lack of trust concerns both "other people" and the government institutions that are needed to implement universal policies.