For decades scholars and journalists in Latin America have written about a "crisis of the family," often linking it not only to changing economic realities but to a corresponding "crisis of masculinity": an image of male profligacy, domestic and public violence, drug and alcohol addiction and abuse, and male unemployment. This dissertation argues that a number of religious and non-religious movements and institutions have converged upon a particular effort to solve this problem (the all-male peer group, modeled on Alcoholics Anonymous), and that this new form of social and religious organization is playing a unique role in reshaping religious life in Latin America. To pursue this argument, the dissertation makes use of over thirty extensive, life history interviews with participants in these programs and with other inhabitants of a rapidly urbanizing center in Costa Rica's rural Northern Zone, where the author conducted twenty-two months of participant-observation and comparative research over nearly a decade with three distinct men's groups as well as three churches (Catholic, evangelical, and Adventist). From this research and from the secondary literature, this dissertation argues that the phenomenon described by Elizabeth Brusco as Latin America's Protestant "reformation of machismo" is considerably broader than evangelicalism alone and is having much broader effects on gender and religion than has been previously appreciated. Much as Robert Wuthnow (1988, 1994a-b, 1998) first pointed out that support group culture has initiated a "restructuring of American religion," a turning away from church hierarchies and towards more egalitarian support groups for a model for spirituality and spiritual community, a similar process appears to be taking place in many parts of Latin America, where Alcoholics Anonymous had by the 1990s more than tripled its North American membership rates. Using a comparative and longitudinal lens, the dissertation argues that these groups are not only renewing men's participation in religion and the family in many parts of Latin America, but are in fact transforming the way gender and religion are understood and co-constructed in the region.