The article focuses on inter-firm relations, primarily seen as protective devises crafted for keeping at an arm's length various kinds of uncertainties involved in boundary transactions. Taking a holistic view, it proposes the notion of relational habitat, which refers to the relatively durable constellation of relations that connect a given firm to its main business partners. Performing a double-edged protective function, this constellation both stabilizes and simplifies the immediate operational domain of the firm and, thereby, diminishes to manageable levels the complexity of the relevant parts of the environment. By expanding the control of the firm beyond its organizational borders, relational habitat reduces the constraining impact of boundary uncertainty and enhances the action capacity of the firm – facilitating the materialization of its chosen line of action and its desired objectives. The article specifies this notion in detail and highlights some of its implications, both for the theoretical development of economic sociology and for its relation to economics.