We describe efforts to formulate a quantitative measurement model for boldness, a construct that has been intensively discussed and investigated in the psychopathy literature in recent years. Although the Fearless Dominance factor of the Psychopathic Personality Inventory (PPI-FD) has served as a major referent for studying this dispositional construct, boldness was not explicitly targeted in developing the PPI, creating the need for a formal measurement model for this construct. Using an exploratory approach to test construction and multiple waves of data collection and analysis involving 1,791 participants, we created nine unidimensional scales (comprising a total of 130 items) for assessing correlated but thematically distinct facets of boldness, and characterized their higher-order structure. Overall scores on this new Boldness Inventory correlated highly with PPI-FD (positively) and dispositional fear (negatively), and negligibly with disinhibitory proclivities, in validation samples consisting of undergraduates (N = 767) and male prisoners (N = 326). The structural model of this new inventory, encompassing a general factor on which all facet scales loaded and two subordinate factors defined by residual variances of certain scales, effectively accommodated the constituent scales of PPI-FD. The model development work reported here establishes a valuable foundation for further, more fine-grained investigation of boldness as it relates to psychopathy and other clinical conditions as well as to adaptive functioning and performance. (PsycINFO Database Record (c) 2019 APA, all rights reserved).