Need for cognitive structure (NCS) could affect stereotypical thinking. In the present paper, it is suggested that the effect of NCS on stereotyping is moderated by the ability to achieve cognitive structure (AACS). NCS is defined as the preference to use cognitive structuring (versus piecemeal processing) as a way to achieve certainty. AACS is defined as the extent to which individuals are able to use information processing processes (cognitive structuring or piecemeal) consistent with their level of NCS. Two studies were conducted to examine this hypothesis. The first examined the effect of NCS and AACS on negative stereotypes held by Israelis towards Palestinians. The second examined the effect of NCS and AACS on perceived in-group (psychology students) and out-group (engineering students) variability. Results of both studies showed that for high-AACS participants, higher NCS was associated with greater stereotypical thinking, whereas for low-AACS participants, higher NCS was associated with less stereotyping.