© The Author(s) 2018. The need for cognition refers to people’s tendency to engage in and enjoy thinking and has become influential across social and medical sciences. Using three samples from the United States and the United Kingdom (N = 1,596), we introduce a six-item short version of the Need for Cognition Scale (NCS-18). First, we reduced the number of items from 18 to 6 based on the items’ discrimination values, threshold levels, measurement precision (item information curve), item–total correlations, and factor loadings. Second, we confirmed the one-factor structure and established measurement invariance across countries and gender. Finally, we demonstrated that while the NCS-6 provides significant time savings, it comes at a minimal cost in terms of its construct validity with external variables such as openness, cognitive reflection test, and need for affect. Overall, our findings indicate that the NCS-6 is a parsimonious, reliable, and valid measure of need for cognition.