Over the past decade, behavior analysts have increasingly used the term establishing operation (EO) to refer to environmental events that influence the behavioral effects of operant consequences. Nonetheless, some elements of current terminology regarding EOs may interfere with applied behavior analysts' efforts to predict, control, describe, and understand behavior. The present paper (a) describes how the current conceptualization of the EO is in need of revision, (b) suggests alternative terms, including the generic term motivating operation (MO), and (c) provides examples of MOs and their behavioral effects using articles from the applied behavior analysis literature.DESCRIPTORS: motivation, establishing operations, abolishing operations, motivating operations, behavior-analytic terminologyThe term establishing operation (EO), originally used by Keller and Schoenfeld (1950) and then by Millenson (1967) to denote motivating events, has been revived and reformulated in a series of papers by Michael (e.g., 1982Michael (e.g., , 1983Michael (e.g., , 1988Michael (e.g., , 1993aMichael (e.g., , 1993bMichael (e.g., , 2000. Michael defined EOs as environmental events, operations, or stimulus conditions that affect an organism's behavior by altering (a) the reinforcing or punishing effectiveness of other environmental events and (b) the frequency of occurrence of that part of the organism's repertoire relevant to those events as consequences. Michael termed the first effect the reinforcer-establishing effect and the second effect the evocative effect. Unconditioned establishing operations (UEOs) do not require a learning history to change the effectiveness of consequences. In contrast, conditioned establishing operations (CEOs) acquire their motivating function as a result of a particular learning history. Michael