Sensitivity to environmental influences varies among individuals. Such differences in sensitivity have been associated with various psychological, physiological, and genetic factors. One of the established psychological markers of environmental sensitivity is Sensory Processing Sensitivity (SPS), a heritable trait which can be measured reliably with the Highly Sensitive Person (HSP) scale, originally developed by Aron and Aron (1997). However, research over the last three decades has revealed several shortcomings of the original HSP scale (i.e. poor coverage of some key characteristics and bias towards negative experiences) whilst the conceptualization of sensitivity shifted from a unidimensional to a multidimensional trait, necessitating a revision of the original scale. This study introduces and validates the revised HSP scale (HSP-R) using a UK and USA sample of 1,000 adults. Exploratory factor analysis on a calibration subsample (n = 600) yielded a 6-factor, 18-item structure, which was confirmed in a validation subsample (n = 400). The HSP-R measures six dimensions of sensitivity: Sensitivity to Details, Depth of Processing, Social Sensitivity, Sensitivity to Positive Experiences, Emotional Reactivity, and Overstimulation. It demonstrates robust psychometric properties, aligns with theoretical frameworks, and provides incremental validity beyond the Big Five personality traits.