We develop a unified theory of exclusive dealing and exclusionary bundling. In a framework with two competing manufacturers which supply their product(s) through a monopolist retailer, we show that buyer power restores the profitability of such practices involving inefficient exclusion. The mechanism underlying this exclusion is that the compensation required by the retailer to renounce selling the rival product erodes with its buyer power. Among others, we further show that our theory holds when the buyer power differs across manufacturers or when the retailer can strategically narrow (or expand) its product assortment.