Entrepreneurs face a host of potential choices in creating new firms, yet little is known about how multiple institutional actors promoting different practices and technologies can affect entrepreneurial decision-making, especially at the beginning of new sectors and technological lifecycles. Using historical data and quantitative analyses of U.S. biodiesel producer foundings, technological innovation and diversity, I highlight the impact of competing institutional actors (agriculture trade associations) on entrepreneurial decision-making and activity. I posit that greater competition or heterogeneity of trade associations promoting various technologies will result in higher rates of biodiesel foundings as well as technological variation and innovation. I also analyze the moderating influences of competing institutional actors (Sierra Club/environmental lobby actors) and entrepreneurial network relations (captured by de novo and de alio entrants) on trade association effectiveness. In a final analysis, I explore the moderating influence of institutional actor size on actor heterogeneity. The dissertation contributes to the growing nexus of institutions and entrepreneurship research as well as to the research on technology entrepreneurship.