Humans and other animals find mental (and physical) effort aversive and have the fundamental drive to avoid it. However, doing nothing is also aversive. Here, we ask whether people choose to avoid effort when the alternative is to do nothing at all. Across 12 studies, participants completed variants of the demand selection task, in which they repeatedly selected between a cognitively effortful task (e.g., simple addition, Stroop task, and symbol-counting task) and a task that required no effort (e.g., doing nothing, watching the computer complete the Stroop, and symbol-viewing). We then tabulated people's choices. Across our studies and an internal meta-analysis, we found little evidence that people choose to avoid effort (and hints that people sometimes prefer effort) when the alternative was doing nothing. Our findings suggest that doing nothing can be just as costly-if not more costly-than exerting effort. (PsycInfo Database Record (c) 2023 APA, all rights reserved).