The concept of mindfulness has enjoyed much resonance among researchers. Despite this past work, we argue there is a need for a domain-specific conceptualization and measure of financial mindfulness (FM). We first define FM as “the tendency to be highly aware of one’s current objective financial state while possessing an acceptance of that state,” and, second, develop and validate an eight-item scale to measure individual differences in FM. This article has nine studies, including a field survey administered by a financial services provider to examine actual behavior. Importantly, the FM-Scale is associated with financial behaviors (i.e., sunk cost bias) above and beyond related scales (i.e., money management stress, self-control, and general mindfulness). To the best of our knowledge, our work is the first to provide a succinct way to measure FM that incorporates elements of both awareness and acceptance, highlighting the role of financial acceptance specifically.