Objectives: Despite daytime factors being implicated as having a key perpetuating role in many of the recent cognitive models of sleep disturbance, standardized, validated measures of sleep-related daytime processing are rare. The aim of the present studies was to develop, refine, and psychometrically evaluate the Sleep Preoccupation Scale (SPS), a self-report tool that examines levels of daytime sleep-related processing. Methods: The SPS is constructed using a quantitative content analysis of responses from a survey of older adults (n=116). The scale is then refined using principal components analysis on a general population sample (n=456), and finally, the convergent validity is examined in a general population sample (n=722). Results: The results suggest the SPS is a reliable and valid measure of sleep-related daytime processing and discriminates different sleeper groups (poor, average, and good sleepers). Conclusion: The findings are related to the models of poor sleep and, in particular, insomnia, and future directions are discussed.