What the empirical evidence suggests about the relationship between parental involvement in noninstructional educational activities or wider networks of community engagement on the one hand and effective schools and student learning on the other is explored. Parent participation is discussed as direct involvement in school governance or as indirect participation in school-community collaborative efforts. It is generally agreed that schools need parental and community involvement to succeed. The concept of social capital refers to features of social organization that improve the productiveness of individuals and groups. As a concept, it originated in claims about the effects of social networks and norms in education in America. The empirical basis of those claims remains controversial, largely because of methodological difficulties, but there is good reason to suspect that many forms of social capital influence education powerfully, including the family, community engagement, and parent-school engagement. Preliminary exploration of three independent measures of educational outcomes (National Assessment of Educational Progress scores, Scholastic Assessment Test scores, and statewide dropout rates) strongly suggests that greater attention should be paid to the possible educational consequences of differing levels of social capital at both family and community levels. These findings raise questions about the methodology, causes, and mechanisms involved in social capital influences on education. Much effort will be needed to test theories linking social capital and educational outcomes and to develop effective social capital intensive strategies for improving education in America. Dilemmas associated with these efforts include equity-efficiency tradeoffs, the link between government and social capital, inclusive versus exclusive social capital, and disparities in class, status, and power. For all its promise, strengthening social capital is not an antiseptic, risk-free strategy for improving education. (SLD)