As broad interest in entrepreneurship increases, one can find researchers, educators, policy-makers, and even investors speaking about the ‘entrepreneurial mindset’. But what, exactly is an entrepreneurial mindset? And how can it be measured effectively? The modern view of an entrepreneurial mindset considers cognitions and behaviours as well as more enduring personality dispositions. The challenge, of course, is to identify the dimensions that matter. Based on a broad literature review, 76 separate descriptions of aspects that could affect entrepreneurial behaviour were identified. Elimination of overlaps produced a list of 37 different constructs. Using the existing literature, the authors produced 116 items that were pilot tested on 400 individuals (217 females, 183 males) in South Africa. The present chapter describes the scale development in detail.