This study explores the specific types of social relationships that influence initiation into and involvement in informal businesses. In particular, it examines the social capital possessed by Amish entrepreneurs who establish home-based, off-the-books tourism businesses. This paper theoretically refines social capital by identifying three dimensions of social relations: cognitive, reciprocal, and structural. I explore the relationship between social capital and Amish involvement in tourism businesses by using measures of tie strength, expected roles in one's network, structural equivalence of network position, common culture, and religion. The results suggest that neither tie strength nor diversity alone accounts for one's involvement in informal entrepreneurship. Rather, a combination of both strong and diverse ties is positively related to informal business involvement and success. Therefore, researchers of entrepreneurship should give attention to the multiplicity of both network tie strength and diversity.