This study argues for and tests the prediction that cognitions about not performing a behavior are not simple opposites of cognitions about performing the same behavior because they rely on separate goals. Three behaviors (i.e., eating meat, doing vigorous physical activity, and breastfeeding) are examined, for which performing and not performing are means to different goals. In the context of the theory of planned behavior, the discriminant validity of constructs related to performing and not performing behaviors is tested. Moreover, the simultaneous validities of perceived behavioral control over doing and not doing for the prediction of both intentions and the incremental validity of both intentions in predicting behavior are investigated. Results show that the constructs related to performing and not performing a behavior independently contribute to the prediction of intentions and behaviors. Implications of considering separable motivational systems underlying doing and not doing are discussed.