Social exchange theory (SET) has made significant contributions to research on residents’ support for tourism. Nevertheless, studies are based on an incomplete set of variables and are characterized by alternative, yet contradictory, and theoretically sound research propositions. Using key constructs of SET, this study develops a baseline model of residents’ support and compares it with four competing models. Each model contains the terms of the baseline model and additional relationships reflecting alternative theoretical possibilities. The models were tested using data collected from residents of Niagara Region, Canada. Results indicated that in the best fitted model, residents’ support for tourism was influenced by their perceptions of positive impacts. Residents’ power and their trust in government significantly predicted their life satisfaction and their perceptions of positive impacts. Personal benefits from tourism significantly influenced residents’ perceptions of the positive and negative impacts of tourism. The study provides valuable and clearer insights on relationships among SET variables.